"قَلَم اَلْأُسْتاذة غالي."
Translation:The professor's pen is expensive.
Is there a definitive guide somewhere to all the intermedial sounds that appear in spoken Arabic, like (am i hearing right) the "t" here between "professor's" and "expensive"?
The t sound comes from the ة. And the i sound after it from the genitive case. The genitive has endings -i/-in when the nominative has -u/-un.
So, with all vowels it is قَلَمُ الْأُسْتاذَةِ غَالٍي or transcribed qalam-u l2ustaadha-t-i ghaalii(-n).
Caveat: the final i-sound of غالي has nothing to do with the genitive but is just caused by the final ي.
None. Because you are mentioning the owner right away: الأستاذة
such relation is called Genitive, in which 2 nouns are added together and it resembles the English ('s) or (of) relationship. So, قلم الأستاذة (pen of professor) or (professor's pen). The possession here is controlled by the addition of (AL) to the second term in the compound الأستاذة (which you can imagine it as "of the" in English). The possessive articles or letters are added to the word only when the owner is not mentioned by name, and they are equal to the English (my, your, his, her,.... etc). We don't need those here because the Professor is mentioned indeed. Like, you wouldn't say in English: this is her the professor's pen - Same thing is applicable in Arabic.