Claude recommends different brands when asked in a different language

An AI visibility report built in English can show one leading brand, while the same question in Russian returns a different brand entirely.

Reza Moaiandin, co-founder of SALT.agency, published the study on Search Engine Journal on 13 October 2026. He ran 1,650 Claude Sonnet 5 answers across six buying scenarios, five languages and 40 runs per combination, using DataForSEO's LLM Responses API. The design was prompted by Anthropic's July 2026 report on Claude's values, which sampled around 310,000 real conversations across 20 languages and found Claude leans toward greater warmth in Hindi and Arabic and greater rigor in English and Russian.

The six scenarios and the method

Moaiandin tested six shopping or booking scenarios: a hotel in Tenerife, a return London to Tenerife flight, noise-cancelling headphones under £400, a robot vacuum under £500, a CRM for a small UK business, and project management software for a 50-person UK firm. Each was asked in English, Arabic, Russian, Simplified Chinese and Persian, with web search turned off. Claude was asked to name three options and say which one it would recommend. Brand names stayed in Latin script for 99.8 percent of responses, cleaning up through a text-matching pipeline.

Where the picks swing most

The sharpest effect came in airlines for the London to Tenerife flight. In Persian, Claude picked British Airways 52.5 percent of the time and easyJet 12.5 percent. In Russian, Claude picked easyJet 72.5 percent and British Airways zero percent. Across all five languages, British Airways averaged 24 percent, Jet2 31.5 percent, easyJet 37.5 percent, TUI Airways 5.5 percent and Ryanair 1.5 percent.

Hotels in Tenerife showed smaller but still large swings. Bahía del Duque was Claude's top pick in 43.6 percent of Chinese responses and 7.7 percent of Arabic ones. Hotel Botánico took 32.5 percent in English, 17.9 percent in Arabic and zero in Russian. The top pick overall, Royal Hideaway Corales, ranged from 20.5 percent in Arabic to 50 percent in Persian.

Where the winner holds across languages

Four of the six categories produced the same winning brand in every language, with the fight sitting in second place. Sony took 87 percent of headphone recommendations overall, with English the outlier at 50 percent, where Bose reached 42.5 percent. For CRMs, Zoho won 85.5 percent of recommendations, Pipedrive and Microsoft Dynamics 365 each took under 2 percent, and English was again where the loss was smallest for HubSpot at 22.5 percent.

Roborock took 91.5 percent of robot-vacuum recommendations across every language, with a floor of 87.5 percent in English and Arabic. Monday.com won project management software at 51 percent overall against Asana at 38.5 percent, holding its lead in every language.

What the study cannot explain

Moaiandin writes that one plausible reason Claude recommends British Airways zero times in Russian is that Russia banned UK-registered aircraft from its airspace in February 2022, which British Airways met by suspending its Moscow route the same day. The reason easyJet is picked 72.5 percent of the time in Russian is still an open question in the paper.

The study also notes a scope limit: Claude is not officially offered in mainland China, Russia or Iran, and several countries carry home-grown models for a large share of AI referrals, including Baidu's ERNIE in China and Naver in South Korea. An AI visibility report built against those models is a different piece of work.

Source

Lost In Translation: How Language Changes Which Brand AI Recommends, Reza Moaiandin on Search Engine Journal.