Would you say :
1 -I really appreciated hearing you speak about the strategy that you have for your company. Or 2 - I really appreciated hearing you speaking about the strategy that you have for your company
Which one is grammatically correct? Thanks for your help
The short answer is that both are grammatically correct.
Of the two you suggested, however, I would additionally include that Option 1 is definitely more often used and would sound more native. In the exact context you provided, the action of speaking has been completed (the other person has stopped speaking, since you are now speaking to them) and therefore "hearing you speak" makes more sense to an English-speaking audience.
That is not to say, however, that the other is wrong. Both of these can be used interchangeably.
This link provided by Lambie supports that both are grammatically correct (the same in American English): https://dictionary.cambridge.org/us/grammar/british-grammar/hear-see-etc-object-infinitive-or-ing
