1."What's the point of learning the Arabic language if there are already so many translations of the Qur'an already available?"
It's a very common question. Simplest answer, we have to take into consideration about what is lost in translation. Basically two things lost in translation. Certainly the content is lost, meaning the Arabic language has a lot of words for the same thing. 'Anger' has 10 to 12 different words for it. The word 'person' has 10 to 12 different words for it. Even the word 'human being' you can say 10 to 12 different ways in Arabic. Each one of those ways carry a different connotation. But when I translate them to English, if I use words A, B, C, D or E for human being, the english translation just can say human being. So, certainly something lost in translation as far as contents.
On the other side, there's a matter of style. When Allah speaks in the Quran, He speak in incredibly articulate fashion. It's profoundly creative speech. And when human being translate what Allah says, maybe they can get some of the content but certainly the creativity and the uniqueness of the words is entirely loss.
Just like when you try to translate poetry or song, from one language to another, maybe you can translate the word but you couldn't translate the creativity and the beauty.
2. "If I don't read the Quran or don't understand the Quran in Arabic or don't learn Arabic, am I lesser Muslim? Am I sinful?"
It is actually an inappropriate question. The fact that you are not Arab or you do not know Arabic, even that itself isn't a sin. Vast majority of Muslims that belong to this Ummah aren't Arabs. So, even that itself the lack of knowledge in Arabic is not the problem. The problem however is when one doesn't feel the desire to learn the language of the one who created them.
You know, the question that should be asked instead in this place is "Am I a lesser Muslim if I have no desire to learn this language even when Allah said that He made it easy" . He is the one who himself send the Quran, "with no doubt we make the Quran easy for remembrance". So, if Allah guarantee that the learning of the Quran is easy, then I should be motivated automatically to learn it. InsyaAllah
3. "The Qur'an calls itself clear, so why do I have to learn this complicated language to understand the Qur'an? Why Can't I simply read the translation?"
Now, the answer to this question is very simple. It's a confusion between two different words. The Quran calls itself clear and clarifying. The Arabic word is "Mubin" which mean clear and clarifying. But that doesn't mean that it is simple. The Quran does not saying that it is simple.
You know, if there's a very difficult calculus problem and I write a really clear solution to that problem, there is no guarantee that the answer to that problem is simple. But it is a guarantee that it is clear. The Quran deal with complex issues. Sometimes very intricate one. It's response and guidance towards those issue is clear. But it doesnt necessarily mean that it self explanatory is simple. So, the two words shouldn't be confuse to each other.