I don't speak Russian

If you do not speak Russian at all, and you are approached or need to ask something yourself, say straight out that you do not speak the language:

Извините, я не говорю по-русски. - Sorry, I don't speak Russian.
Я не умею говорить по-русски. - I can't speak Russian.
Я не владею русским языком. - I don't speak Russian.

If you speak a little Russian, but still find it difficult to have a proper conversation, then say so:

Я не очень хорошо говорю по-русски. - I don't speak Russian very well.

Я немного говорю по-русски. - I speak Russian a little.
Я очень плохо говорю по-русски. - I speak bad Russian.
Я говорю по-русски очень медленно. - I speak Russian very slowly.
Я могу сказать только несколько слов по-русски. - I can only say a few words in Russian.
Я понимаю русский, но не говорю по-русски. - I understand Russian, but I don't speak Russian.

Sometimes the interlocutor may not immediately understand that you do not speak Russian. Then you can additionally mention that you don't understand anything and ask again. Or use these phrases yourself right away:

Я не понимаю (вас). - I do not understand (you).
Повторите, пожалуйста. - Repeat, please.
Не могли бы вы повторить, пожалуйста? - Could you repeat, please?
Простите, что вы сказали? - Excuse me, what did you say?
Что, простите? - Excuse me, what?
Говорите медленнее, пожалуйста. - Speak more slowly, please.
Не могли бы вы говорить медленнее, пожалуйста? - Could you speak more slowly, please?
Напишите это, пожалуйста. - Please, write it down.
Не могли бы вы написать это, пожалуйста? - Could you write this, please?

Note: some phrases overlap in meaning, but the situations in which they are used differ. Those phrases that begin with "could you...." are recommended to be used in a formal setting.

In addition, you can ask your interlocutor if he or she speaks your native language and communicate further so that you both understand: А вы говорите по-английски / по-французски / по-китайски? - Do you speak English / French / Chinese?

How do you say that in Russian?

And finally, if you still want to learn Russian little by little and get acquainted at least with individual words, you can use clarifying phrases. Or, for example, you liked a dish in a restaurant and you want to order the same thing in another place, you can clarify how certain words sound or are spelled in Russian:
Как это говорится на русском? - How do you say it in Russian?
Как это сказать по-русски? - How to say it in Russian?
Как это по-русски? - How is it in Russian?
Как будет по-русски ...? - How will be in Russian ...?
Как сказать по-русски ...? - How to say in Russian ...?
Что значит ...? - What does ... mean?
Я не знаю, как это будет по-русски. - I don't know how to say it in Russian.

A sample dialogue might look like this:

- Извините, я не очень хорошо говорю по-русски. Вы не поможете мне? / Excuse me; I don't speak Russian very well. Could you help me?

- Да, конечно. Чем я могу помочь? / Oh, sure. How can I help?

- Я ищу ... Вы говорите по-английски? Как сказать по-русски bus stop? / I'm looking for ... Do you speak English? How do you say "bus stop" in Russian?

- По-русски это «автобусная остановка». Она находится за углом этого дома. / In Russian it is «bus stop». It is located around this house corner.

- Повторите, пожалуйста. / Please, repeat.

- Остановка за углом. Вон там. / The stop is around the corner. Over there.

- Спасибо! / Thanks!

We hope that having learned the phrases that will help you say that you do not speak Russian; you will feel more confident when communicating with Russian-speaking interlocutors. In addition, if you still want to master the Russian language, we are waiting for you at the Russian school as a foreign language Leader.

A source: https://golearnrussian.com/how-to-say-i-dont-speak-russian/