So, what I understand here is that the first sentence is:
"I understand, that Russian (is) difficult to study (the process of learning it), but I like this.
and the second sentence is:
"I understand, that "to have learned Russian" (as a completed action) is difficult, but I like this.
I translate the verbs изучать = to study (process of learning)
and выучить = to learn ( to have learned)
Is that the difference between these two verbs??
Thanks!