Both do make sense - i.e. you would be understood using either - but number 1 is definitely more natural and what most native speakers would say. Even more natural is "It's difficult for me to speak English" or "I find speaking English difficult". Also, 'nuance' in this context sounds quite stilted - a better way of putting it would be "give me an idea", "give me a clue", or "explain to me the difference".

As for me, the first sentence is more natural, but without preposition "in". I think, that the nuance is only in using The Infinitive form in 2 sentence. It isn't easy for me, to speak English. ^_^

what is meanıng nuance?

The first is more natural :)

To speak in english is not an easy thing for me. That would be the more natural way of saying it, using the infinitive form of the verb- "to be" In general though, you would avoid that "to"-form-verb, especially if it isn't a generalization(something that you personally did not do) ex. To work with no break can damage your body. It also gives a more formal feel, thus i changed "isn't" to "is not" But normally I would say use the 1st option. And even so, I find it is even more natural, if you say "Speaking in English is not easy for me" Try listening to more english, and then you'll somehow feel the natural way saying it. ps. i second what LGF92 said about the nuance