Most verbs in Arabic are built around a trilateral root, consisting of three consonants. For example, the word دَخَلَ (dakhala) which means “to enter”. The root of the word is د + خ + ل . The consonants will remain the same, no matter what tense the verb is in. As in Spanish, verbs in Arabic are conjugated (change form, depending on pronoun). In the “present” tense, it works like this, with use of a prefix (ت - “ta” , ي - ya, or ن - na) along with modifying the vowel pattern. The root consonants remain the same. The following example is in the “past” or perfect tense, with a suffix attached to the root.
He entered - دَخَلَ (dakhala)
She entered - دَخَلَتْ (dakhalat)
You (m. sing.) entered - دَخَلَتَ (dakhalata)
You (f. sing.) entered - دَخَلَتِ (dakhalati)
I entered - دَخَلَتُ (dakhalatu)
They (dual m. - 3rd person) - دَخَلا (dakhala)
They (dual f. - 3rd person) - دَخَلَتَا (dakhalata)
You (dual 2nd person) entered - دَخَلْتُمَا (dakhaltuma)
They (m. pl) entered - دَخَلُوا (dakhalua)
They (f. pl) entered - دَخَلْنَ (dakhalna)
You (m. pl) entered - دَخَلْتُمْ (dakhaltum)
You (f. pl) entered - دَخَلْتُنَّ (dakhaltunna)
We entered - دَخَلْنَا (dakhalna)

Arabic does not have an exact equivalent of the “present” and “past” tense, as used in English. Instead, it has the “perfect” and “imperfect” tenses. Perfect tense is used to describe actions that have been completed, such as “he ate” but not “he was eating” which is imperfect (incomplete action in the past or present). The above example is the perfect tense, describing completed actions in the past. The above is also in the “active” voice (”he entered”), rather than “passive” which would be “he had entered”.

When looking up words in the dictionary, verbs are given in the male singular third person (”He”), in the perfect tense. For example, you would find “to enter” listed as دَخَلَ (dakhala).

A standard greeting, with some Islamic connotation is:

Peace be upon you - أسَّلامُ عَليكُم (ah’salaamu ah’leeokum) with the response و عَليكُم السلام (wa ah’leeokum a’salaam) - And peace be upon you (reply)

Sometimes you may hear added on, أسَّلامُ عَليكُم و رحمة الله (ah’salaamu ah’leeokum wa rahmatu allah), which means “Peace be upon you and Mercy of Allah”.

Or, you might hear an even longer greeting: أسَّلامُ عَليكُم و رحمة الله و بركات (ah’salaamu ah’leeokum wa rahmatu allah wa barakatuh) - “May the Peace, Mercy and Blessings of Allah be upon you”

This article in the Arab News explains more about the use of greetings in Arabic:

Muslims all over the world use the Islamic form of greeting, assalamu alaikum, which means “peace be to you.” The very wording helps generate a friendly and relaxed atmosphere. It is also common in its shorter and longer forms to all Muslim communities wherever they happen to be. Thus, when two Muslims meet who are total strangers to each other, the moment they use this greeting, they immediately feel that they have common ground, even though they do not speak each other’s language. The Islamic greeting has different versions, the shortest of which is the one we have already mentioned. The rule in Islam is that when we are offered a greeting, we return it with a better one, or with its equal at least. (read more)

كَيفَ الحال؟ (kayf hal) - How are you?
Alternatively, one might say “Keyf heh lak” (to a male) or keyf heh lik (to a female).
When asked this question, one is expected to respond positively, no matter what one is feeling. You should answer by saying الحَمدُ لِلةِ بِخَير (al-hamdu lila bikheer) which translates as “Thank God, I am well”. بخَير الحَمدُ لِلةِ (bikheer al-hamdu lila) is also acceptable.
Alternative to “how are you?” in Egypt:
Izzayyak (to a male); response: Kwayyis, il-hamdu lillaah, which means “fine, thank you”;
Izzayyik (to a female); response: Kwayyisa, il-hamdu lilaah;
Izzayyukum (to a group); response: Kwayyisiin, il hamdu lilaah;
Other questions:
Izzaay il-awlaad - how are the children?
Izzaay il-madaam - how is madam? (your wife)