1- What kind/dialect of Arabic language is better to study for travel and reading? Check this thread out: https://www.italki.com/post/Z8N2ak0zMFjBOwvglDViSn You'll find a somewhat concise and comprehensive answer to this question. As for which dialect, the best and most straightforward answer, really, is: Whichever you want. Iraqi, Egyptian, Levantine, Moroccan, Khalidji (Gulf Dialect) etc. are all valid options and understood by most Arabs. 2- What does it mean Modern Standard? "Modern" speaks for itself, I think. It's to differentiate it from "Classical". "Standard" means that it has mapped-out and unified grammar, structures and pronunciation. So everyone in any country speaks and writes it the same way. Dialects have no grammar per se. You won't find, for example, "Iraqi Grammar" or " Egyptian Grammar" books. 3- Is it easily understandable by people in all Arabic countries? Yes. 4- Is Modern Standard also similar to Classical language? "Similar" is a very relative term, but I will go for a yes for now. They are not completely different languages, of course. They have so many similarities, but also many differences. Vocabularywise, new words have been added the Modern Arabic that you won't find in the Classical. And that's natural, because technology and science develop continuously, so vocabulary must be expanded accordingly. Many words in the Classical are obsolete and not used anymore in the Modern. Pronunciation is identical in both languages. The modern Arabic today is pronounced more or less exactly like it was a 1400+ years ago. Grammar is also essentially the same, but alot of structures of the Classical are out of use in the Modern. You can think of the Modern as the "simplified" Classical. Unless you have a high proficiency in the Arabic language, it will be difficult to understand classical Arabic books and texts. So in a nutshell, the two are essentially the same language. They're just two varieties of the same language.

For travel and reading, modern standard arabic is the best to learn and it’s the official language in every arab country so everyone understand it.And every single arabic country have its own dialect which is unofficial but people speak it in their daily life

Furqan A. Фуркан, огромное спасибо за исчерпывающий и очень интересный ответ! Я хотела бы Вам предложить сотрудничество по русско-арабскому языковому обмену. Если это Вас интересует, напишите мне на почту.

Thank you! This is good news. Is Modern Standard also similar to Classical language?

أصدقائي أنا معلمة لغة عربية خريجة جامعة دمشق عملت ك معلمة للغة العربية لمدة ٤ سنوات لدى خبرة في تعليم المبتدئين والكبار وطرق التعبير الادبي اتمنى من يحتاج إلى دروس أن يتواصل معي💜