Can Turnitin detect AI in non-English submissions?

Four, as of 18 August 2026. That is the day Turnitin added Modern Standard Arabic to English, Spanish and Japanese, and its own file requirements page still says three, so check the date on anything you read about this, including this. A file in a language outside those four is outside what an AI Writing Report is documented to handle. And the rule is about the language of the file you submit, so a paper drafted in Portuguese and submitted in English is an English submission.

From Turnitin's file requirements for an AI Writing Report, as that page stood on 21 August 2026:

"File must be written in a supported language: English, Spanish, Japanese"

Alongside it, on the same short list: "Accepted file types: .docx, .pdf, .txt, .rtf". That line is current. The language line is three days behind.

Arabic went live on 18 August 2026 and the requirements page has not been edited since. The release notes entry for that date is headed "New AI detection writing detection capabilities for Modern Standard Arabic submissions", and the product updates page puts it in one sentence: "Arabic detection will run alongside our English, Spanish, and Japanese detectors". So the working list is four. If you click through to the requirements page and count three, you have found a page that has not caught up, not a contradiction. German, Chinese, Portuguese and Korean are on neither version of it.

This is the part that rarely makes it into the summaries. The FAQ page covering AI writing detection opens by limiting itself: "The following content and FAQs pertain to our AI writing detection capabilities for English submissions only." Directly under that line sit three links out: one to a Spanish FAQ, one to a Japanese FAQ, and one to an Arabic FAQ. The release note says why in plainer words: "our Arabic AI writing model is a separate model from our English AI writing, Spanish AI writing, and Japanese AI writing models".

And the capability that looks for text run through paraphrasing or bypasser tools is English-only. Turnitin's page on using the AI Writing Report says "only our English AI detector includes AI paraphrasing and AI bypasser detection capabilities", and the sentence right after it: "At this time our Spanish and Japanese AI detectors do not include AI paraphrasing or AI bypasser detection capabilities." That page has not been revised for Arabic and still names only two. The Arabic detector does not slip through the gap: Turnitin's Arabic-language FAQ answers the question on its own page, saying AI paraphrasing detection is currently available only in the English detector. That page is in Arabic; the English wording of it here is ours.

Do not read that as an opening. Read it as a reminder that "Turnitin's AI detection" is not one uniform thing, and that anything you have read about how it behaves was almost certainly written about the English detector.

The requirement is about the file. If you drafted in your first language and the document you upload is in English, it is the English text that gets segmented and scored, regardless of where the ideas were first written down.

Which raises the question people are really asking: does machine-translated prose look like model output? Turnitin has not published anything that answers it directly, and nobody outside Turnitin has the access it would take to answer it properly. What Turnitin has published is the list of properties that turn up in its own false positives:

"Sometimes false positives (incorrectly flagging human-written text as AI-generated), can include content without a lot of structural variation, text that literally repeats itself, or text that has been paraphrased without developing new ideas."

Translated academic prose can land on all three, not because the writer did anything wrong, but because translation tends to regularise sentence shape. That connection is our inference, not Turnitin's statement.

Turnitin's own next sentence is the one to carry into a meeting with a supervisor: "If our indicator shows a higher amount of AI writing in such text, we advise you to take that into consideration when looking at the percentage indicated." The vendor is on record telling the people who read these reports to factor that in.

Its FAQ says the training sample deliberately included "statistically under-represented groups like second-language learners, English users from non-English speaking countries, students at colleges and universities with diverse enrollments and less common subject areas such as anthropology, geology, sociology, and others to minimize bias when training our model".

That is the company's account of its own process, and it comes with no published bias figures. Treat it as a stated intention. The separate question of who actually gets flagged more often has its own evidence, and we went through it in why non-native English writers get flagged more often.

Before you assume a two-page reflection is the low-risk case:

"In shorter documents where there are only a few hundred words, the prediction will be mostly 'all or nothing' because we're predicting on a single segment without the opportunity to overlap."

The line after that: "This means that some text that is a mix of AI-generated and original content could be flagged as entirely AI-generated." Short pieces are where translation-heavy writing and all-or-nothing scoring meet, and that combination produces the reports that are hardest to argue with.

My paper is in German. Will it get an AI score? German is not on the supported-language list for an AI Writing Report. Whether your institution's setup does anything else with the file is a question for the institution, not something Turnitin's documentation covers.

I wrote it myself, then used a translation tool. Is that AI-generated? Those are two different questions and only your institution answers the first one. Disclosure rules increasingly cover translation as well as drafting, so read the actual policy rather than assuming translation is exempt.

Does the Spanish detector work the same way as the English one? Not identically, and nor does the Japanese or the Arabic one. Turnitin describes all four as separate models, the paraphrase and bypasser layer is documented as English-only, and the main FAQ limits itself to English submissions and sends the other three languages to pages of their own.

My university uses Turnitin, but I have never seen an AI percentage. You would not. Turnitin says only instructors and administrators can see the indicator, though instructors can download the report as a PDF and share it. And AI detection requires a specific licence, so some institutions have none at all.

Does the model try to identify which AI tool was used? No. It classifies segments by probability of being likely human or likely AI-generated (more on what that measurement is).