أنا دائما أتكلم العربية في البيت، وأحيانا أتكلم الإنجليزية في العمل.

Yes, أنا is optional here. Arabic verbs already show the subject through conjugation, so أتكلّم by itself means I speak.

• With أنا: adds emphasis/contrast (e.g., As for me, I always…) or clarity.
• Without أنا: more neutral and very common: دائماً أتكلم العربية في البيت…

It’s the present tense (imperfect) verb with the أ- prefix, which marks 1st person singular:

• أتكلّم = I speak / I am speaking
  Other examples for comparison:
• يتكلّم = he speaks
• نتكلّم = we speak

In Modern Standard Arabic, the imperfect can cover both meanings depending on context:

• Habitual/general: I speak
• Ongoing (right now): I am speaking
  In this sentence, دائماً and أحياناً make it clearly habitual.

Adverbs of frequency commonly come before the verb in Arabic:

• دائماً أتكلم… = I always speak…
• أحياناً أتكلم… = I sometimes speak…
  You can also place them after the verb (especially in some styles), but before the verb is very typical and clear.

دائماً means always. The ـاً is usually tanwīn fatḥ (an “-an” ending) often seen on adverbs in MSA. In fully vowelled text it’s دائِمًا. In normal unvowelled writing, you still often see ـاً on common adverbs like:

• دائماً (always)
• غالباً (often/mostly)
• أحياناً (sometimes)

When Arabic names languages, it commonly uses the definite form with الـ:

• العربية = Arabic
• الإنجليزية = English
  It’s like treating them as known/standard categories. You may also see اللغة العربية (the Arabic language) for extra clarity/formality.

في means in and is the normal preposition for locations/contexts:

• في البيت = at home (literally in the house)
• في العمل = at work (literally in the work/workplace)
  Arabic often uses في where English uses at.

Yes, و is and, but it also smoothly links clauses in a very common Arabic way. Here it connects two related habits:

• Clause 1: I always speak Arabic at home
• Clause 2: and sometimes speak English at work

Because the word begins with a hamza (glottal stop). In Arabic orthography, many words starting with a vowel sound are written with أ (hamza on alif). You’ll commonly see:

• أحياناً (sometimes)
• أنا (I)
• أتكلم (I speak)

Often yes. Both can mean to speak:

• أتكلّم is very common for speaking in general.
• أتحدّث can sound a bit more formal or like to converse / to talk (about something).
  In this sentence, either works naturally: دائماً أتحدّث العربية… is acceptable MSA too.