Arabic stative verbs and the like

[Inun-Ea]

As-salāmu ˤalaykum,

I have a question concerning those verbs of arabic whose meaning seems to equal that of their roots' respective adjectives or participles. I would like to know what the difference between the following pairs is, if it is a matter of the speaker's preference, of dialect, of language style or level etc.

a) Stative verbs: Some verbes have the vowel /u/ in their perfect stem. Their meaning usually is: "To be [meaning of the resp. adjective]. Examples would be حَسُنَ ḥasuna "to be good" existing along with حَسَنٌ ḥasan^un, صَغُرَ ṣaġura "to be little, small" next to صَغِيرٌ ṣaġīr^un etc. You will certainly know more of them.
But what is the actual meaning of هو يحسن huwa yaḥsun^u and هو يصغر huwa yaṣġur^u compared to هو حسن "he is good" and هو صغير "he is small" or, if the meaning is the same, what other difference is there?

b) Some verbs seem to have a meaning "to be [meaning of the resp. adjective] for someone". They are in the Vth stem, for example تَعَسَّرَعليهtaˤassara ˤalayhi "to be difficult for someone" next to the stative عَسُرَ ˤasura "to be difficult" and the adjective. Is it also possible to say هذا عسير لي "This is difficult for me"?

c) I wonder particularly in what the use of the present tense of verbs like اِشْتَاقَ ištāqa differs from the use of the participle. Is there a difference of any kind between أشتاق إليك 'aštāqu ilaykⁱ and أنا مشتاق إليك 'anā muštāq^un ilaykⁱ? I am even more confused by reading that the past tense is normally used, so people when are asked to translate "I miss you" or the like tend to answering not أشتاق إليك aštāq^u ilayk but اشتقت إليك ištaqt^u ilayk. What, then, would be the finite, i.e. conjugated, verbal form corresponding to كُنْتُ مُشْتَاقًا إِلَيكِ kunt^u muštāq^an ilaykⁱ?

I would be really happy if someone could help me out of my confusion. Thank you in advance.
Now, let me end my post by congratulating you to such a beautiful mother tongue!

[Ectab]

thanks for congratulating us, I am really happy to be able to speak Arabic as my mother tongue, and sorry for the late reply.

well, your question has many parts, the past verb stem of u, give of like what English use verb to get Sagura-yaSguru (to get smaller\small) in my opinion is better to be translated as to get... rather than to be.
huwa yaSguru (he\it gets\is getting\will get small\smaller,
huwa Sagura (he\it got\has gotten small\smaller
huwa Sageer (he\it is small

it is hard to explain the difference between 3asura and ta3asarra, but you can understand it this way:
3asura to get hard, ta3assara is the intransitive verb form of 3assara (to make (something) hard) so ta3assara means to be made hard (because of something\someone) or something like that
3aseer is an adjective means hard

ishtaaqa means "he miss" lit: he missed, we use the past tense because the action of missing occured and finished despite whether it is still continuing or not, we would not use the non-past yashtaaq because it sounds like: he miss (habitual) or is missing (progressive) or will miss (future)
mushtaaq is the participle, participles in Arabic are used to describe ones state "he is in state of missing) but this is not usually used in MSA but dialects.