If you don't speak English either:
* "Moi non plus." (Me neither.) This is the simplest and most direct response.
* "Je ne parle pas anglais non plus." (I don't speak English either.) This is a more formal way of saying the same thing.
If you can speak some English:
* "Un peu." (A little.) This is a good response if you understand some English but aren't fluent.
* "J'essaie d'apprendre." (I'm trying to learn.) This shows that you're willing to communicate and are making an effort.
* "Je peux parler un peu anglais." (I can speak a little English.) This is a more direct way of saying you understand some English.
If you want to be polite:
* "Pardon." (Excuse me.) This is a polite way to acknowledge their statement.
* "Merci." (Thank you.) This is a polite way to express your understanding.
If you want to use gestures:
* You can shrug your shoulders to indicate you don't understand.
* You can point to yourself and say "Je" to indicate that you are the one who doesn't speak English.
Remember to be polite and patient! Even if you don't speak French fluently, you can still communicate effectively by using these phrases and gestures.