Arabic is one of the most ancient three Semitic languages (Arabic, Babylonian and Canaanite). There are other, more recent, Semitic languages like Aramaic and Hebrew.|
The Arabic language is a very rich and beautiful language. Like most Semitic languages, it is written (and read) from right to left (and top to bottom on a page). There are 28 letters (all but the first are consonants).
Good news: Arabic does not have upper/lower case. The grammar remained the same over the past 15 centuries which makes it easy to understand classic texts from the early Islamic and pre-Islamic times. The numerals used by most nations are the Arabic ones (0-9).
Arabic is spoken in all Arab countries and, to some extent, by all Muslims (being the original language of the Qur'an, Islam's revealed book, and Hadith, sayings of prophet Muhammad PBUH). In numbers, Arabic has over 260 million native speakers and is the second language of around 1.3 billion people. It is also one of the main five UN languages.
There are some differences in the spoken langauge across the Arab world and soetimes dialects differ inside the same country, but the written and official language is the same all over the globe - that's the language you see in books, street signs, official document, public speaking, radio and tv. It is easy to pick a regional slang once you learn the standard, but not so easy to go the other way round.
Arabic words consist of letters joined together (Apart from a few exceptions). Handwriting in Arabic is very similar to the printed form. Of course, we cut corners and use conventions, but the uniqueness of a letter and its similarity to the printed form are always preserved (assuming legible writing, of course!). In most cases, short vowels are left out in writing.
As you learn and practice, try to concentrate on what makes a letter unique rather than worry yourself about cosmetics.