AI Localization for Ecommerce: Beyond Translation (Units, Tone, Compliance)

AI localization for ecommerce: why translation is only the first step

AI localization for ecommerce goes beyond translating product descriptions into another language. It means adapting your entire product experience — units, sizing, tone, formatting, regulatory claims, and cultural conventions — so that shoppers in each market feel like the catalog was built for them.

A well-translated product listing that shows dimensions in inches for a German shopper, uses US dress sizes on a French marketplace, or makes health claims that violate EU regulations is worse than no translation at all. It looks careless, erodes trust, and can result in listings being removed or fines being issued.

In 2026, AI tools make localization faster and more scalable — but they still require structured rules and human oversight. This guide covers the specific localization challenges ecommerce teams face and how to solve them.

For the translation step itself (tools, workflows, glossaries), see our companion guide on AI translation for ecommerce catalogs.

Measurement units and format conversion

Unit conversion is the most common and most impactful localization task. Getting it wrong makes products unsellable.

Units to convert by market

Conversion rules

• Always convert to the locally expected unit. Do not rely on shoppers to do the math.
• Round appropriately. 12 inches = 30.48 cm, but display "30.5 cm" not "30.48 cm" for readability.
• Preserve the original unit in parentheses when precision matters: "30.5 cm (12 in)"
• Automate conversion at the data level. Store the base measurement in a standardized unit and apply conversion rules per market in your pipeline.

Currency and price formatting

Beyond conversion rates, formatting differs:

• US: $1,299.99
• Germany: 1.299,99 €
• Czech Republic: 1 299,99 Kč
• Japan: ¥129,999 (no decimals)

Ensure your catalog system handles both conversion and formatting per locale.

Sizing conventions: clothing, shoes, and beyond

Sizing is a major source of returns and customer dissatisfaction when localization is done poorly.

Key sizing systems

Clothing:

Shoes:

Localization rules for sizing

• Display the local sizing system first. On a German marketplace, show EU sizes prominently with US/UK equivalents secondary.
• Include size charts. Link to a size chart with cross-market equivalents on every PDP with sized products.
• Standardize variant naming. "Size 42" is clearer than "Large" on EU marketplaces. Use the locally expected format.

Tools like Lasso help standardize attribute values at the source, making it easier to apply market-specific sizing rules during export.

Cultural tone and content adaptation

Language-correct is not the same as culturally appropriate. The way you describe products should match local expectations.

Tone differences by market

• US — direct, benefits-focused, often casual. "This jacket keeps you dry in the worst storms."
• Germany — detail-oriented, technical, specification-heavy. German shoppers expect precise measurements and certifications.
• Japan — polite, detail-rich, quality-focused. Packaging and presentation details matter.
• France — aesthetic, design-focused, quality over features. Lifestyle positioning works well.
• Czech Republic — practical, price-conscious, no-nonsense. Avoid overly promotional language.

Practical adaptations

• Adjust description length. German and Japanese product descriptions tend to be longer and more detailed than US equivalents.
• Localize examples and use cases. A "Thanksgiving entertaining set" means nothing in Europe. Adapt to local occasions and contexts.
• Adapt imagery references. If your description references "your backyard," consider whether the target market typically has backyards.
• Adjust formality. Some markets expect formal address (German "Sie"), others prefer casual.

For more on writing product descriptions that resonate, see our guide on product descriptions that sell.

Regulated claims and market-specific compliance

This is where localization becomes legally consequential. Claims that are acceptable in one market may be restricted or illegal in another.

Categories with significant regulatory differences

Health and supplements:

• EU has strict EFSA-regulated health claims. You cannot say "boosts immunity" without an approved claim.
• US FTC requires "structure/function claims" to be truthful and not misleading, but the bar is different from EU.
• Some ingredients legal in one market are restricted in another.

Cosmetics:

• EU Cosmetics Regulation requires specific labeling, INCI ingredient lists, and restricts certain marketing claims.
• US FDA regulates cosmetics differently — fewer pre-market requirements but strict post-market enforcement.
• "Hypoallergenic" has different legal weight by market.

Electronics and safety:

• CE marking required for EU market entry
• UL certification expected in US
• Electrical specifications differ (110V/60Hz vs 220V/50Hz)

Environmental claims:

• EU Green Claims Directive (effective 2026) requires substantiation for all environmental claims
• Terms like "eco-friendly," "sustainable," and "biodegradable" face increasing regulation
• Greenwashing penalties are growing across markets

Localization approach for compliance

• Build a claims database per market that lists what you can and cannot say
• Flag claims during translation that need market-specific review
• Strip or adapt claims that are valid in the source market but not in the target
• Add required disclaimers per market (energy labels in EU, Prop 65 in California, etc.)

For deeper coverage of compliance in AI-generated product copy, see our article on keeping AI product copy compliant.

Category-specific terminology and glossaries

Different markets use different terminology for the same product attributes, even within the same language.

Examples

• "Sneakers" (US) vs "trainers" (UK) vs "turnschoenen" (NL)
• "Pants" (US) vs "trousers" (UK)
• "Duvet" (UK/EU) vs "comforter" (US)
• "Capsicum" (AU) vs "bell pepper" (US)

Building market-specific glossaries

Extend your translation glossary with market-specific terminology:

1. Identify high-impact terms in your top categories
2. Research local terminology — what do shoppers in each market actually call this product?
3. Map variants — create a lookup table from your canonical term to market-specific terms
4. Apply during localization — use these mappings in your translation/localization pipeline
5. Update from search data — use local search query data to identify terms shoppers use

For how to standardize supplier data that feeds into this process, see our guide on standardizing supplier product data with AI.

Getting started with ecommerce localization

Localization is an ongoing process, not a one-time project. Prioritize based on market revenue and regulatory risk:

1. Start with units and sizing — these are the most common sources of returns and customer complaints
2. Build compliance rules per market — especially for regulated categories
3. Create market-specific glossaries — start with your top 3-5 markets
4. Adapt tone guidelines — document how descriptions should differ by market
5. Automate what you can — unit conversion and formatting should be rules in your pipeline, not manual edits

Lasso helps teams standardize the source data that feeds localization — enriching attributes, normalizing values, and structuring content so market-specific rules can be applied cleanly. Explore pricing or book a demo to see how it fits your localization workflow.