The truth is that the difference in dialect between Arabic countries is trivial and any observed difference from one dialect to the other is merely a difference in accent. With that in mind, don't be disheartened by various online dictionaries or translation services which list Arabic as Egypt-Arabic, Lebanon-Arabic, KSA-Arabic and so forth. If you look at the the actual translation the words are the same.
Take a look at Google Android and Apple iOS for example. Switch your language and phone display between different Arabic and there is no difference at all.
How a particular word is pronounced is the real difference and this isn't considered an error among Arabs since there are so many accents that learning formal Arabic and informal Arabic is merely a case of pronouncing the word in a neutral tone. Sure, there are a few words unique to each Arab country but they just that: unique. In the main, Arabic is Arabic where you go.
Let's look at five phrases I believe every Arabic student as well as tourist, traveler or casual should learn. With the following phrases you can literally navigate around any Arab country, converse with Arabs and understand the gist of most Arabic sentences using containing any of these phrases:
1. As-salamu Alaykum:
This phrase is a Muslim greeting but is so widespread that it has been adopted by Arabs from all religious backgrounds. The phrase means "Peace Be Upon You". The first word, As-salamu literally means "Peace" and the second phrase "Alaykum" means "Upon You". You might be wondering why other acceptable phrases such as Hello in Arabic "Hala" are not preferred to a religious greeting.
The reason for this is that saying, "Hello" to a Muslim carries no weight when trying to create a friendly atmosphere and because it's an accepted greeting in all religons, it acts as a catch-all which is the proper greeting for all Arabic backgrounds. The reply given to this phrase is a reverse of this: "Wa Alaykumu As-Salam", the difference being the additional "Wa" which translates to "and", which translates to, "And Peace Be Upon You". This phrase is 100% phonetic i.e. it is spoken exactly as it written: "as sa la mu alay kum" and similarly when returning the greeting. It is also perfectly acceptable to just say the word "Salam" [can you guess what Salam means?]
2. Kayfa Halak:
This phrase is usually said after the greeting discussed above. This translates to, "How is your situation" The word "Kayfa" means "How" and Halak means "Your situation". Put together they informally mean "how are you?". Just like in English when you ask someone, "What's up" you're not literally asking that person what is above their head. So, although "Halak" means situation put together with Halak it has come to mean "How are you". Again this word is pronounced exactly as it is written. In fact, Arabic is a phonetic language in the purest form. There are no letter combinations as in the gh or sh combinations as you see in the English words "Though" or "Should". Master the Arabic alphabet and you can, with little practice, read standard Arabic text.
In reponse to be asked how you are you can reply with several phrases, but the most common are: "Alhamdu-lillah" which means "praise to Allah" or "bi-khayr" which means in good condition.
Ayn means "Where". So, why is Ayn considered a phrase? The reason is that includes the word "is" and it is so prevalant in the language and one of the most useful words to learn when asking for a person, item or places location. The word means "Where".
There is no need to add "is" as in "Where is Ali?", "Where is the cinema?". The Arabic word Ayn includes the "is" part. So, for example, the name of the street you are looking for is called Jordan Street, all you would need to say is: Ayn Shareh Jordan. (Here shareh means "street").
This translates to English as, "Where Jordan Street" which is grammatically incorrect but in Arabic because the word Where [Ayn] includes the word "is" is perfectly acceptable. Look at this example: Ayn Ahmed? Again this translates to "Where is Ahmed?".
4. Shuk-ran and Af-wan
Afwan and Shukran are pronounced exactly as they written above and are used interchangeably and often immediately after the other. Afwan means "Excuse me" and "Sorry" in certain contexts. Shuk-ran means "Thank you". Let's use some examples to see how these two words would be used together:
A waiter has just finished serving you. You say "Shukran" which means thank you and he says "Afwan" back. We learned above that Afwan means "Sorry" or "Excuse Me" so what is the waiter apologising for? Simply put: he is not. Afwan in this context means "I'm sorry for not doing enough".
In other words he is not apologising but it is more of a welcome on steroids, they are being humble and being extra courteous but they are not actually apologising for any wrong they think they have done.
When someone says thank you in the Arab world always acknowledge it with an "Afwan".
However, in other contexts the word "Afwan" does actually mean "Sorry". Apologising for bumping into someone by accident, hurting someones feelings or being discourteous is easily remedied with a simple "Afwan". There is also another word for apology in Arabic and that is "Samih-nee" but that is used in serious wrongs and literally means "Forgive me" as opposed to a simple "Sorry".
5. Ma asalama
A good greeting As Salamu Alaykum above can be undone with a bad farewell, especially in Arab countries where simply getting up and leaving with a simple hand gesture or nod is considered the height of ill manners. Instead always leave by saying: "Ma asalama". If you remember when we discussed the greeting "Asalamu Alaykum" we learned that the word Salam means "Peace".
The root wood is always "Salam". In a greeting we added "As-" and in our farewell we added an "a" on the end, so it is pronounced "Ma-asalama". We have also added the word "Ma" before the word Peace. "Ma" means "with".
The phrase, therefore, literally translates to: "With Peace" but in a social setting means "I leave you with peace" or "Go in peace".
Another farewell that is taught in Arabic classes is, "ila Al-Liqah" which means "till next time" but this is generally not used among Arabs and is used by tourists and is too formal even in business settings.
It is the same as saying "I bid you farewell" when among English friends. Also, "ila liqah" does not convey the warmth of the word "Peace".
The above should be a good foundation for further study. Remember to practice and apply these phrases in daily life till they become second nature. Ma asalama!