Arabic sits in the FSI's hardest tier, though not because of the script. Twenty-eight letters that map to sounds is a fortnight of work. The real difficulty is that short vowels are left out of ordinary writing, that prefixes and suffixes attach with no space, and that the written standard differs from every spoken variety. A reader that resolves an unvocalized word on the first tap removes most of the first two.

The US Foreign Service Institute places Arabic in Category IV, at roughly 2,200 class hours, or about 88 weeks of intensive study, to reach professional working proficiency. Reading is a much shorter road than speaking. With lookups a tap away and practice ordered by frequency, simple news text comes within reach long before that figure.

Both, for different jobs. Everything written — news, books, Wikipedia, signage, official documents — is Modern Standard Arabic, and it is shared across every Arabic-speaking country. Everything spoken at home is a regional variety, and which one you want depends on where you are going. Lector teaches the standard, because that is what reading needs and because it is the one variety that is useful everywhere.

No. Ordinary Arabic does not print them, so a learner who depends on them cannot read a newspaper. Lector keys its dictionary on the unvocalized spelling instead, which is why a word from running text resolves at once, and it shows the vocalized spelling in the definition so you learn the vowels as you read. Typed practice accepts an unvocalized answer, because nobody types the marks.

A deliberately multi-region Modern Standard voice, not a national accent. Google publishes Arabic speech as ar-XA for exactly this reason, and Lector uses it, so the audio does not teach an Egyptian or a Gulf accent to somebody who has not chosen one.