Style presets without the cloud: what we measured

You dictate a rough thought, and the app can rewrite it in a chosen tone before it lands in the field: neutral, friendly or professional. The rewriting is done by the language model that Apple builds into macOS 26. No text leaves the Mac. Before building it, we measured whether it works for Russian.

The spike

Before building anything we ran a throwaway experiment. We wrote ten realistic business phrases in Russian: a short chat reply, a polite refusal, a request to a colleague, a few with English terms inside. We pushed them through the model in different tones, including deliberately extreme ones such as a pirate or a melodrama, so that differences were easy to see.

There was an obvious catch. The model supports 23 languages, and Russian is not one of them. A model can still produce a smooth text from a language it does not know, by guessing from familiar word pieces, and by eye a good guess is hard to tell from real understanding. So we agreed to treat a suspiciously smooth result as a reason for doubt, not as proof of quality.

The verdict from the live run was that the quality is usable, free and works offline. The model also has a hard limit: 4,096 tokens for the instructions, the input and the answer together.

0 out of 30

The key question was the direct path: Russian text in, Russian text in another tone out. We counted it honestly, with a log that records which path produced each result. Ten phrases in three tones made 30 attempts. The direct path worked 0 times. All 30 went to the fallback, and the fallback never failed.

The fallback goes through English. The Russian text is translated into English with Apple’s translation, the English is rewritten in the chosen tone, and the result is translated back. The chain ends in plain safety: if any step fails or the needed language pack is missing, you get your original text, never a half result. On the key that does not translate, English text is never pasted by mistake.

We still left the direct attempt in the code. Russian is expected in the next generation of the model, which comes with macOS 27. When it arrives, the direct path starts working without a change on our side. Until then it costs a fraction of a second per failed attempt, and we accepted that.

What went wrong in live testing

The friendly tone sometimes answered the text instead of rewriting it: a greeting, a comment nobody asked for, an offer to help. It was worst on short phrases. We added an explicit instruction that the model rewrites and does not reply, and then put it into every tone, because the failure was not tied to one tone. Another trap: when the model hits its length limit, it stops without an error and returns a cut-off text as if it were fine. We check whether the answer ends like a sentence, and fall back if it does not.

Escape cancels styling at any moment. On August 7 the dictation panel also got a style switcher, and the instructions for each tone can be edited.

Today: styles run on a small model that the app downloads on your request, so Apple’s model is no longer required.