Silent gratitude:

Using silence as a way for practice, you can always use your mind mind and express gratitude in silence
to the person you learn Buddhism from.
Not all can use their mind mind.

So, some use their brain mind and express their gratitude verbally which results in the right speech
as well as gaining right Karma for having expressed it in wholesome speech.
If there is a way to earn good Karma why do you not like to indulge in it.
To do the right thing start with doing it right within the sangha.

If you do not start right here to practice doing it right including expressing it in right speech where do you think you can do it.
This is the arena, this is the practice area, this the plowing field,for you to sow the good seeds for Karma.
Start sowing good Karma seeds so you may reap them in the future.

That's part of the practice of Buddhism.
Buddhism is not just for learning in silence.
Do it and double your merits after learning it by expressing it rightfully.

Palms together
Deep bows,
Des/boo-ngoh