subjunctive mood (indicating a hypothetical state or a state contrary to reality, such as a wish, a desire, or an imaginary situation).
But here in your example you are talking about a possible proposition that could happen in the future.
So you don’t need to use if in subjective mood, unless you’re talking about an imaginable matter that has never taken place in the past and can’t never take place in the future.
So the right tense according to your sentence goes like:
- If you use these phrases in speech, people will be impressed. (First condition)
We use first condition when i want to talk about something could happen in the future:
I you pass Your exam , Your father will award you. [if something happens present tense, the second thing would follow future tense
- If you used these phrases in speech, people would be impressed. (Second condition)
We used the second condition about something like .
For example: if someone told you not to study for the exam, so you failed:
Then i would come to tell you :
If you studied for the exam, you would pass the exam. ( here, i am talking about a condition that could happen in the past, but didn’t happen because you hadn’t studied for the exam.
But it differs from the subjunctive mood, as the subjunctive mood indicate to unreal “impossible thing to happen” it uses just for imagining.
Like: If I were a lion, I would not live here.
Look here, I can never ever be a lion, so it is just imagination. Can’t take place in reality.
- If you had used these phrases in speech, people would have been impressed. (Third condition)