I am learning French because I want to study abroad.

I hope this site helps me to practice in the language which I interested in. Lovely :)

(It's 'helps' becasue it refers to 'the site' therefore you need it in the 3rd person. I put 'to practice' but you can also say, 'to improve' or 'to get better'

When you use the word 'in' with any noun like 'in the house', 'in the car', 'in the language' you always need to put the definate article 'the' in between the noun the preposition 'in'

I am not sure why it is 'to be interested in' but this is what it is and always need to be written as the whole thing. It is a compund verb and the English language is full of them so it is just a case of learning them!)