Three mistakes almost every English speaker makes
None of them involve the subjunctive. They're translation reflexes, and two lessons are usually enough to unlearn them.
After a few years of teaching, you start hearing the same three mistakes from nearly everyone. None of them involve the subjunctive or complicated tenses: they're translation reflexes.
The first: saying « je suis 34 ». In French you have your age, you aren't it. « J'ai 34 ans » — and the reflex goes within days once you hear yourself say it out loud.
The second: reaching for « je suis en train de » constantly, because English leans on the continuous. French is happy with the simple present. « Je travaille » already means you're working right now.
The third is subtler: word-for-word politeness. « Est-ce que je peux avoir… » is fine, but « je voudrais » sounds like someone who has spent time in France. Small shifts like this change how you're heard entirely.
None of these stop you being understood. They only signal that you're still translating in your head — which is precisely what we work on.