AI search engines evaluate multilingual sites using several key factors that go beyond classic SEO signals. In practice, models behave more like regional experts than simple translation engines. Experts summarize their approach as follows:

• Language Match: AI tools first check if a version of your content exists in the query's language. When someone asks in Spanish, the models look for Spanish pages first. Weglot's data confirms this: untranslated Spanish sites had vastly more visibility in Spanish searches than in English.

Conversely, ChatGPT and Perplexity often answered foreign-language questions in the user's language but still linked to English pagesgsqi.comstanventures.com. In short, if you only have English content, AI sees no relevant answer for non-English queries.

• Translation Quality: The translation must be fluent and nuanced. AI models are highly sensitive to awkward machine translations. Generic, literal translations tend to confuse AI.

In other words, stiff or error-ridden translations are likely to be deprioritized.

• Cultural Relevance: Local context matters. AI favors content that reflects the user's region; from local currency and regulations to cultural references.

For example, a pricing page showing USD only feels less relevant to a Mexican user than one showing MXN. Content localized for region (including examples, idioms, local laws, dates and number formats) signals to the model that you understand the audience. This cultural resonance boosts AI trust.

• Cross-Language Consistency: Trustworthiness is signaled when your brand messaging and facts match across languages. Inconsistent details or claims can make AI less confident in citing your site. Keeping your product details, specifications, and positioning aligned in every language helps AI see your site as reliable.

• Authority Amplification: Having content in multiple languages itself boosts site authority in AI's eyes. Even within English answers, sites that also had Spanish pages got more citations. In fact, translated sites earned 24% more citations per query on average. This happens because multilingual sites naturally attract more backlinks and usage, signaling trust.