I read it somewhere that Muslims must learn Arabic (The language of Islam) I know how to read the Q'uran in Arabic but I don't know how to speak Arabic and I also don't understand a single word that I read in the Q'uran in Arabic without seeing the translation . So tell me do I have to learn the Arabic in spite of the reading.
I would always bare in mind the following hadeeth:
'Aishah (May Allah be pleased with her) reported: The Messenger of Allah (ﷺ) said, "The one who is proficient in the recitation of the Qur'an will be with the honourable and obedient scribes (angels) and he who recites the Qur'an and finds it difficult to recite, doing his best to recite it in the best way possible, will have a double reward."
[Al-Bukhari and Muslim] (https://sunnah.com/riyadussaliheen/9)
From experience of being a non Arabic reader (I started learning in my mid 20's). I found that the more I read, and in particular read along with slow reciters, the better I got (both in terms of speed and accuracy).
I was not happy reading and not understanding, so reading a translation did help for a period of time, and this is what I would recommend. In terms of a long term solution, I moved abroad for a period of time to become proficient in understanding the language, and this then provided yet further depth of meaning.
To answer your question, you absolutely DON'T have to understand what you are reading, but the better you understand then the more you will benefit from it.
If you have the time and the ability, the best is to read, write, speak Arabic, but also reflect on what you read in the Quran.
If you cannot cannot write and speak Arabic yet, then read and listen to the Quran.
If you cannot read Arabic yet, then listen to the Quran.
If you do not understand Arabic, still listen to the Quran. A baby does not understand mother's words, but the mothers voice still offers comfort.