Short Vowels of Arabic

The first thing that threw me off is the short vowels.  In Arabic script, short vowels are implied typically, so words are spelled with consonants.  For teaching words or reading religious texts, there are diacritical marks used to denote the proper sound of the consonant with the implicit short vowel:

• the fatḥa (فتحة‎‎) appears as [ـَ] and represents a short short /a/.  
• This sounds like the a in cat. 
• Arabic example: <دَ> /da/.
• the kasra (كسرة) appears as [ـِ] and represents a short /i/.  
• This is like the sound of i in sit.  
• Arabic example: <دِ> /di/.
• the ḍamma (ضمة) appears as [ـُ] and represents a short /u/. 
• This is like the sound of u in put.  
• Arabic example: <دُ> /du/.

For speakers of Spanish or Japanese, these will be unique sounds.  This sort of threw me off as I typically used Spanish as a platform to learn other languages, transliterating the sounds to match Spanish phonology, which won't help in this case.