No. English does not have to be your mother tongue. We recommend basic English knowledge, and the affirmations work for you as long as you have had some contact with the language.
Think about what your mind is doing while a program runs. The affirmations sit quietly underneath the music, and your subconscious picks up the meaning. Meaning is the part that matters. If a sentence like "I am confident" already carries a clear idea for you when you read it, your mind can work with it.
What basic English means here
You do not need to speak fluently, write essays or hold a conversation without thinking. School English is enough. So is years of English music, films and internet. Most people who ask this question already have more than they think.
The scripts are written in plain, everyday sentences. Short lines, present tense, simple words. There is no jargon and no poetry to decode.
Read the sample affirmations if you are unsure
Every product page lists sample affirmations from that program. That is the honest test. Read through it, and if the lines make sense to you on paper, they will make sense to your subconscious.
Here is where to find the scripts. You can look one over before you buy anything.
If a few words are new to you
Look them up once. Ten minutes with the script and a translator, and the vocabulary is yours. After that the program does its work in the background while you go about your day.
Your accent, your grammar and your speaking confidence have nothing to do with any of this. You are listening, not performing.
Everything else works the same for you
The listening advice does not change with your first language. Keep the volume between 10 and 50 percent, use headphones where you can, and give it 2 to 4 weeks of regular listening before you judge the results. Deeper changes usually show up over 2 to 3 months.
There are 90 days of money back on every program, so you have room to try this and see how it lands for you. If you want to hear the difference between the versions first, the comparison is here, and this page explains how the audio is built.