Without learning Arabic, one cannot understand the meaning and essence of the Quran. In order to understand the words of Allah, a Muslim should understand the feeling and nature of the Quran. It is not possible to achieve this benefits without learning the Arabic language.
Some of us knows Arabic upto some extent but that is not enough to understand the word of Allah i.e Quran. The Sahabas (Companions of Prophet Muhammad (sw) also knew Arabic, but yet Allah commands our Beloved Prophet Muhammad (sw) to teach them Quran:
لَقَدۡ مَنَّ اللّٰهُ عَلَى الۡمُؤۡمِنِيۡنَ اِذۡ بَعَثَ فِيۡهِمۡ رَسُوۡلًا مِّنۡ اَنۡفُسِهِمۡ يَتۡلُوۡا عَلَيۡهِمۡ اٰيٰتِهٖ وَيُزَكِّيۡهِمۡ وَيُعَلِّمُهُمُ الۡكِتٰبَ وَالۡحِكۡمَةَ ۚ وَاِنۡ كَانُوۡا مِنۡ قَبۡلُ لَفِىۡ ضَلٰلٍ مُّبِيۡنٍ
Surah Ali Imran 164
"Surely Allah conferred a great favour on the believers when He raised from among them a Messenger to recite to them His signs, and to purify them, and to teach them the Book and Wisdom. For before that they were in manifest error."