Here is a collection of Arabic dictionaries and bi-languages of English and Arabic. You can find dictionaries like Mawurid, oxford English – Arabic dictionaries among others.
There also other books related to understanding the Arabic language.
For example, there are books concerning Arabic grammar, phrases, and so on.
Arabic as a language focused on this side due to the fact that the Holy Quran is revealed in Arabic.
It is a general assumption from scholars that learning Arabic and understanding it helps much in understanding Islamic theology.
But more importantly, helps in understanding the meaning of the Arabic holy Quran and the Books of the prophetic traditions.