difficult

[Allifathima]

1. I find it difficult to comprehend his speech.
2. I find difficult to comprehend his speech.
2a. I find difficult to understand his speech.
Are all these sentences OK?
In #1 sentence, what does 'it' refer to?

[Dozy]

Only #1 is correct.

"it" is a dummy pronoun which is grammatically required but does not refer to any tangible thing.