World map showing app store revenue distribution by region with highlighted countries for app localization priority including Japan, Germany, South Korea, and Brazil.

You know you should localize your app. Every ASO guide tells you that non-English markets represent over 70% of global app revenue.^[1] But localizing into 40 languages at once is overwhelming. You have limited time, limited budget, and no idea which languages will actually move the needle.

The truth is that not all languages are created equal. Japanese generates 3-4x more revenue per download than Hindi. Brazilian Portuguese gives you access to 200 million mobile users with booming app spend. German app users have some of the highest willingness to pay in the world. Meanwhile, some languages that look impressive on paper — like Mandarin Chinese — come with distribution challenges that can make the ROI complicated.

This guide gives you a data-driven framework for choosing which languages to localize into first. We will break down the top markets by revenue, downloads, and competition, then give you a tiered priority list you can start executing today. Whether you have budget for 3 languages or 30, you will know exactly where to focus.

The Data Behind Language Prioritization

Before picking languages, you need to understand the global revenue landscape. The app economy is not evenly distributed, and the countries that download the most apps are not always the ones that spend the most money.

Revenue concentration is extreme. The top 5 markets — the United States, Japan, China, South Korea, and the United Kingdom — account for roughly 75% of global app store revenue.^[2] If you are optimizing for revenue rather than raw download numbers, these are the markets that matter most.

iOS vs Android revenue splits vary dramatically by country. Japan and the United States skew heavily toward iOS in terms of revenue, with Apple's App Store generating 2-3x the revenue of Google Play in those markets. Germany and South Korea are more balanced. Brazil, India, and Indonesia are overwhelmingly Android markets. This matters because your localization strategy should account for where your target platform dominates.

Download volume does not equal revenue. India generates the most app downloads globally but ranks far lower in revenue. Indonesia and Brazil have massive download numbers but lower average revenue per user (ARPU). Conversely, Switzerland, Norway, and Japan have relatively modest download volumes but extremely high ARPU. Your prioritization depends on whether you monetize through purchases, subscriptions, or ad revenue.

The language-to-market relationship is not always 1:1. Spanish covers Spain and 20 Latin American countries. Portuguese covers both Brazil and Portugal. French covers France, Belgium, Switzerland, Canada, and much of West Africa. When you localize into French, you are not just unlocking France — you are unlocking every French-speaking market where your app is available. This multiplier effect makes certain languages disproportionately valuable.

With this context, let us build the priority tiers.

Tier 1: The 5 Languages You Should Localize Into First

These are the languages that offer the best combination of high revenue, high demand, and manageable competition. If you can only localize into 5 languages, start here.

1. Japanese

Market size: Japan is the second-largest app market by revenue, generating over $25 billion annually.^[3] Japanese users spend more per capita on apps than any other nationality.

Why it matters: Japanese users almost never download English-only apps. Unlike markets where English serves as a usable fallback, Japan has extremely low tolerance for non-localized content. Localizing into Japanese is not optional — it is a prerequisite for any visibility in this market. The competition from localized apps is also lower than you might expect because many Western developers skip Japan entirely due to the perceived difficulty of the language.

Revenue potential: Very high. Subscription apps and games perform exceptionally well. In-app purchase ARPU in Japan is 3-4x the global average.

Localization complexity: High for manual translation (three writing systems, cultural nuances, honorific levels), but AI-powered localization tools handle Japanese metadata well because the context is constrained to titles, descriptions, and keywords. You do not need to localize your entire app UI to see significant listing-level results.

2. Korean

Market size: South Korea is the fourth-largest app market by revenue, punching well above its population of 52 million.^[2]

Why it matters: Like Japan, South Korea is a market where English-only listings get ignored. Korean users are highly engaged mobile consumers — the country has one of the highest smartphone penetration rates in the world and some of the fastest average connection speeds. App spend per user is among the top 5 globally.

Revenue potential: Very high for gaming, entertainment, and productivity apps. Korea's gaming market alone exceeds $6 billion annually.

Localization complexity: Moderate. Korean uses a single alphabetic system (Hangul) and has relatively consistent grammar patterns. It is one of the more predictable languages for AI translation in app metadata contexts.

3. German

Market size: Germany is the largest app market in Europe, and German-speaking markets (Germany, Austria, German-speaking Switzerland) represent over 100 million potential users with high purchasing power.^[4]

Why it matters: German users have the highest willingness to pay for apps in Europe. The market is mature, with strong subscription adoption and low churn. Unlike some Asian markets that require significant cultural adaptation, German localization is relatively straightforward for Western developers because the cultural context is more familiar.

Revenue potential: High. Germany's ARPU rivals the US for many app categories. Business, productivity, and health apps do particularly well.

Localization complexity: Low to moderate. German has compound words that can create character-limit challenges in titles and subtitles, but AI tools like AppDrift handle metadata generation with character-limit awareness built in.

4. French

Market size: French is spoken across France, Belgium, Switzerland, Canada, and over 20 African nations. France alone is the second-largest European app market, but the total addressable French-speaking audience exceeds 300 million globally.^[5]

Why it matters: The multiplier effect. When you localize into French, you unlock not just France but every French-speaking market simultaneously. This makes French one of the highest-leverage languages for ASO because a single localization effort covers multiple high-value markets. French Canadian users also respond strongly to French-language listings, even though English is widely understood.

Revenue potential: High. France has strong app spend, and the combined French-speaking market is substantial.

Localization complexity: Low. French is well-supported by every translation tool and has minimal ambiguity in app store metadata contexts.

5. Portuguese (Brazil)

Market size: Brazil is the largest app market in Latin America and one of the top 5 globally by download volume. Over 200 million potential users, with rapidly growing smartphone adoption and app spend.^[2]

Why it matters: Brazil is an Android-dominant market with exploding growth in fintech, social, and entertainment apps. Brazilian Portuguese (pt-BR) is meaningfully different from European Portuguese (pt-PT) — you should localize specifically for Brazil, not use a generic Portuguese translation. Brazilian users are highly engaged but price-sensitive, making freemium and ad-supported models particularly effective.

Revenue potential: Moderate to high. Revenue per user is lower than Japan or Germany, but the sheer volume of users makes up for it. Brazil's app economy is growing at 20%+ annually.

Localization complexity: Low. Brazilian Portuguese is well-handled by AI translation tools. The main consideration is ensuring you use pt-BR specifically, not pt-PT, as the differences in vocabulary and phrasing are noticeable to native speakers. Check out our guide on translating your app store listing for practical tips.

Tier 2: The Next 5 for Serious Growth

Once you have Tier 1 covered, these languages open up massive additional markets. The revenue per user may be slightly lower or the competition higher, but the scale makes them essential for any app pursuing global reach.

6. Chinese (Simplified)

Market size: China is the single largest app market in the world by download volume and second by revenue. However, access is complicated by the absence of Google Play and Apple's unique position in the Chinese market.^[6]

Why it matters: If your app is available on the iOS App Store in China, localizing into Simplified Chinese is non-negotiable. The market is simply too large to ignore. Beyond mainland China, Simplified Chinese also serves Chinese-speaking communities in Singapore, Malaysia, and globally. The challenge is that competition in China is fierce, and user acquisition costs are among the highest in the world.

Revenue potential: Extremely high in absolute terms, but ROI depends heavily on your app category and distribution strategy.

Localization complexity: Moderate. Character limits work differently because Chinese characters convey more information per character than alphabetic languages. Your 30-character App Store title can say much more in Chinese. Cultural adaptation matters more than in European languages.

7. Spanish

Market size: Spanish covers Spain plus 20 Latin American countries, reaching over 500 million native speakers. Spain is a mid-tier European market, but Mexico, Colombia, and Argentina add significant volume.^[7]

Why it matters: The reach-to-effort ratio of Spanish is exceptional. A single Spanish localization makes your app discoverable across an enormous geographic area. Latin American markets are growing rapidly, with smartphone adoption still climbing in several countries. Spanish also serves the large Hispanic market in the United States, adding domestic value.

Revenue potential: Moderate individually per country, but the aggregate is substantial. Latin American markets are growing faster than mature markets.

Localization complexity: Low. Spanish is one of the most straightforward languages for localization. Regional variations exist (Spain vs Latin America), but for app metadata, a neutral Latin American Spanish works across most markets. Learn more about how localization drives installs in our comprehensive guide.

8. Italian

Market size: Italy is the third-largest app market in Europe and has strong consumer spending on mobile apps, particularly in gaming, fitness, and lifestyle categories.

Why it matters: Italian users strongly prefer native-language content. The market is less competitive than Germany or France for localized apps, meaning your localized listing faces fewer alternatives. Italy's app spend has been growing steadily, and the country's high smartphone penetration means the addressable market is mature.

Revenue potential: Moderate to high. Italy ranks consistently in the top 10 for app store revenue in Europe.

Localization complexity: Low. Italian is well-supported by all translation tools and has predictable metadata patterns.

9. Russian

Market size: Russian serves over 250 million speakers across Russia, Ukraine, Kazakhstan, Belarus, and other former Soviet states. Russia alone is the largest app market in Eastern Europe.

Why it matters: Russian-language users represent a significant and underserved market. Many Western developers skip Russian localization due to geopolitical concerns, but the users in these markets still actively use the App Store and Google Play. This creates lower competition for localized listings, meaning a well-optimized Russian listing can rank higher more easily than in saturated markets like English or Japanese.

Revenue potential: Moderate. ARPU is lower than Western European markets, but volume compensates. Gaming and utility apps perform particularly well.

Localization complexity: Moderate. Russian uses the Cyrillic alphabet, which means your metadata will look completely different from Latin-script languages. AI tools handle this well, but you should review character limits since Cyrillic words tend to be longer.

10. Turkish

Market size: Turkey has a population of 85 million with one of the fastest-growing app markets in the EMEA region. Smartphone penetration exceeds 80%.

Why it matters: Turkey is a bridge market between Europe and the Middle East, with rapidly growing digital spending. Turkish users download more apps per capita than most European countries, and the market is underserved by localized Western apps. Gaming, social media, and fintech apps have seen explosive growth.

Revenue potential: Moderate but growing rapidly. Turkey's app revenue has doubled over the past 3 years.

Localization complexity: Low to moderate. Turkish uses the Latin alphabet with some additional characters. The agglutinative nature of Turkish grammar can create long words, but this rarely causes issues in short metadata fields.

Tier 3: Long-Tail Languages for Maximum Coverage

These languages are worth pursuing when you have exhausted Tier 1 and 2, or when AI translation makes the marginal cost near zero. Each individually contributes less revenue than Tier 1-2 languages, but collectively they can add 15-25% to your global downloads.

Dutch

The Netherlands and Belgium (Flanders) are small but affluent markets. Dutch users have high smartphone adoption and strong app spending habits. The market is small enough that localization gives you a significant competitive advantage over English-only competitors.

Polish

Poland is the largest app market in Central and Eastern Europe after Russia. Polish users are price-conscious but highly engaged, particularly in gaming and utility apps. The market is growing faster than most Western European countries.

Thai

Thailand has a rapidly growing mobile-first economy with over 50 million smartphone users. Thai users are heavy app consumers, particularly in social media, e-commerce, and gaming. Localization into Thai is uncommon among Western developers, giving localized apps a significant discovery advantage.

Vietnamese

Vietnam has nearly 100 million people and one of the fastest-growing digital economies in Southeast Asia. App downloads are growing at over 30% annually. The market is Android-dominant and price-sensitive, but volume is enormous.

Arabic

Arabic covers over 20 countries across the Middle East and North Africa, with combined populations exceeding 400 million. The Gulf states (UAE, Saudi Arabia, Qatar) have extremely high ARPU, rivaling Western European levels. Arabic is a right-to-left language, which requires consideration in screenshots and UI, but metadata localization is straightforward.

Hindi

India's app market is the largest in the world by download volume but monetization is challenging. Hindi localization makes sense if your app uses an ad-supported model, targets the growing Indian middle class, or operates in categories like education, finance, or entertainment where Indian users are increasingly willing to spend.

Indonesian

Indonesia is the fourth most populous country and the largest app market in Southeast Asia by downloads. App revenue is growing rapidly as mobile payments and subscriptions gain traction. Indonesian (Bahasa Indonesia) is one of the easiest languages to localize into, with simple grammar and Latin script.

How to Evaluate a Market Before Localizing

Picking languages from a tier list is a good starting point, but your specific app may have different dynamics. A fitness app might perform unusually well in South Korea. A finance app might find its best market in Brazil. Here is a framework for evaluating any market before committing to localization.

Step 1: Assess revenue potential. Look at the total app revenue for your category in the target market. App Annie (now data.ai), Sensor Tower, and AppTweak all provide country-level revenue estimates by category. If your category generates less than $10 million annually in a market, the opportunity may be too small to justify localization effort.

Step 2: Evaluate competition density. Search the App Store and Google Play in the target language for your primary keywords. Count how many results are actually localized into that language versus English-only. Low localization density means your translated listing will face less competition and rank more easily. This is why markets like Turkey, Thailand, and Poland can outperform their size on paper — Western competitors have not bothered to localize.

Step 3: Estimate localization cost. With traditional translators, each language costs $50-200 for a full listing translation. With AI-powered tools like AppDrift, the marginal cost of adding a language is near zero once you are on a plan. Factor in both initial translation and ongoing update costs when calculating ROI.

Step 4: Check platform distribution. If your app is iOS-only and the target market is 90% Android (like India or Indonesia), the addressable market is much smaller than headline numbers suggest. Conversely, a premium iOS app in Japan is targeting the most lucrative mobile audience in the world.

Step 5: Score and rank. Use a simple scoring model: Revenue Potential (1-5) x Competition Level (1-5, inverse — less competition = higher score) x Localization Cost Efficiency (1-5). Multiply the three scores and rank your language list by total score. This gives you a data-driven priority order customized to your specific app.

The formula looks like this:

Priority Score = Revenue Potential x (6 - Competition Density) x Cost Efficiency

A language with high revenue potential (5), low competition (score 5 because density is 1), and high cost efficiency (5) would score 125. A language with moderate revenue (3), high competition (score 2 because density is 4), and moderate cost efficiency (3) would score 18. The difference is dramatic, and it prevents you from wasting localization effort on languages that look good on paper but offer poor practical ROI.

The Fast Path: Localizing to 40+ Languages at Once

Everything in this guide so far assumes the traditional constraint: localization is expensive, so you must prioritize ruthlessly. But what if that constraint no longer applies?

The economics of app localization have shifted fundamentally. With AI-powered metadata translation, you can translate your entire app store listing into 40+ languages in minutes for a fraction of what a single human translator would charge. AppDrift's Starter plan at $9.99/month gives you access to 40+ languages with AI-powered cultural adaptation and keyword optimization for each target market.

This changes the strategy entirely. Instead of agonizing over which 5 languages to start with, you can launch in all 40+ simultaneously and let the data tell you which markets respond. Here is why this approach increasingly makes sense:

The marginal cost is near zero. Once you have optimized your English listing, translating it into an additional language with AI takes seconds, not days. The incremental cost of adding language 6 through language 40 is negligible. There is no economic reason to leave markets on the table.

You discover unexpected markets. Data consistently shows that apps find users in markets developers never would have predicted. A meditation app might gain traction in Thailand. A budget tracker might take off in Poland. By launching in all available languages, you let the market self-select rather than relying on your assumptions about where demand exists.

Long-tail languages compound. Individually, markets like Dutch, Norwegian, or Czech contribute modest downloads. But collectively, 20 small markets can generate more total revenue than a single large market. The long tail is real, and the only way to capture it is to be present in those languages.

AI translation quality has crossed the threshold. Modern AI translation tools trained on app store content produce metadata that reads naturally to native speakers. The quality is not perfect — a human translator will still catch nuances that AI misses — but for app metadata (titles, subtitles, descriptions, keywords), the quality is sufficient to drive discovery and downloads. Users judge your app by the experience, not by the perfection of your store listing grammar.

The "pick 5 languages" strategy made sense when each language cost $200 and took two weeks. When each language costs pennies and takes seconds, the optimal strategy is to localize everything and optimize the winners.

If you are ready to take this approach, start by connecting your app to AppDrift and running a full multi-language translation. Then use one-click publishing to push your localized metadata to both App Store and Google Play across all markets simultaneously. Within weeks, your analytics will reveal which languages drive the most organic growth — and those are the markets worth doubling down on with deeper localization efforts.

For a broader look at global launch strategy, read our guide on how to launch your app globally. And if you are curious about the full cost breakdown, our article on app localization costs covers every pricing model in detail.

Common Mistakes in Language Prioritization

Before you finalize your localization plan, watch out for these pitfalls that trip up even experienced developers.

Confusing download volume with revenue. India and Indonesia generate massive downloads but relatively modest revenue. If your monetization depends on subscriptions or premium purchases, prioritize high-ARPU markets like Japan, South Korea, and Germany over high-volume, low-ARPU markets.

Using Google Translate for app metadata. Generic translation tools do not understand ASO keywords, character limits, or app store context. The result is metadata that technically translates the words but misses the search terms users actually type. Use an ASO-aware localization tool that incorporates keyword research for each target language.

Ignoring cultural adaptation. Translation and localization are not the same thing. Translating the words is step one. Adapting the messaging for cultural context is step two. In Japan, app descriptions tend to be detailed and feature-focused. In the US, they are benefit-focused and concise. In Brazil, they lean toward conversational and enthusiastic. An AI tool that understands these cultural differences will produce metadata that converts better than a literal translation.

Localizing metadata but not screenshots. Your app store screenshots are the most influential factor in download decisions. If your screenshots show English UI while your description is in Japanese, the disconnect erodes trust. At minimum, add translated captions to your screenshots. Even better, show localized UI screenshots for your top-priority markets. AppDrift's AI-powered metadata tools can help streamline this process.

Set-it-and-forget-it localization. Your localized listings need updates whenever you change your English metadata, launch new features, or run seasonal promotions. Stale translations hurt rankings and credibility. Build localization updates into your regular release cycle.

FAQ

What are the top 5 languages to localize an app into first?

Based on revenue data and market accessibility, the top 5 languages to localize into first are Japanese, Korean, German, French, and Portuguese (Brazil). These markets combine high app revenue per capita, strong smartphone adoption, and relatively low competition from localized apps. Japanese and Korean users in particular rarely download English-only apps, making localization almost mandatory for those markets.

Is it worth localizing into Chinese if my app is not available in China?

Yes. Simplified Chinese serves not only mainland China but also significant Chinese-speaking communities in Singapore, Malaysia, and globally. Even if your app is not on Chinese domestic stores, Chinese-speaking users on the App Store and Google Play worldwide represent a massive audience. However, if you cannot serve mainland China, prioritize Traditional Chinese (Taiwan, Hong Kong) and Simplified Chinese for Southeast Asian markets.

How much does app localization cost per language?

Traditional human translation costs $50-200 per language for a full app store listing (title, subtitle, description, keywords). For 10 languages, that is $500-2,000 per update cycle. AI translation tools like AppDrift reduce this to $9.99/month for unlimited languages, making the cost-per-language effectively negligible. The economic advantage of AI translation means the old strategy of carefully selecting 3-5 languages is becoming less relevant.

Should I localize into right-to-left languages like Arabic and Hebrew?

Arabic is a high-growth market worth considering as a Tier 2 or Tier 3 priority. The Middle East and North Africa region has rapidly growing smartphone adoption and increasing app spend. However, right-to-left languages require extra attention: your app UI should support RTL layouts, and your screenshots need to reflect this. If your app does not support RTL natively, localize the metadata but flag the UI limitation honestly in the description.

How do I measure ROI after localizing into a new language?

Track three metrics per market: downloads (organic), revenue (or trial starts), and keyword rankings. Use App Store Connect and Google Play Console analytics to compare before and after localization. A well-localized listing typically shows results within 2-4 weeks. If downloads increase but revenue does not, your in-app experience may need localization too. If neither increases, review your keyword strategy for that language to ensure you are targeting terms with actual search volume.

References

Statista. "Worldwide mobile app revenue forecast." statista.com
data.ai. "State of Mobile 2026." data.ai
Statista. "App market revenue forecast — Japan." statista.com
Statista. "App market revenue forecast — Germany." statista.com
Statista. "App market revenue forecast — France." statista.com
Statista. "App market revenue forecast — China." statista.com
Statista. "App market revenue forecast — Mexico." statista.com

International ASO

Best Languages for App Localization: Data Guide