There's a question in OEDILF about the significance of seven vowels in the Dangla language. Is having that many vowels unusual?
Is the Dangla language unique in some aspect?

Is having that many vowels unusual? Is the Dangla language unique in some aspect?

Nope. That's a small number compared to English. The thing is by vowels do you mean glyphs in an alpahbet or phonemes in the language. General American English has the following vowels (though some of them, like /e/ and /o/ only occur in diphthongs):

/i, u, ɪ, ʊ, e, o, ə, ɚ, ɛ, ɝ, ʌ, ɔ, æ, ɑ/

These map (in my dialect) to the following words.

• i, cheap
  
• u, soon, actually /u:/
  
• ɪ, sit
  
• ʊ, put
  
• e, date, actually in diphthong /eɪ/
  
• o, soap, actually diphthong /oʊ/
  
• ə, sofa
  
• ɚ, winner
  
• ɛ, bet
  
• ɝ, herd
  
• ʌ, run
  
• ɔ, caught, actually /ɔ:/
  
• æ, cat
  
• ɑ, cot
  

This is not all of them. There are actually a bunch of Dangla languages in Chad. Which one are they discussing on OEDILF? (link)

My dialect of English has 14 vowels, if you count diphthongs as vowels, which I do. Cree and Adyghe have only three vowels. The language with the most vowels might be Alsatian German, with 21 (at least according to Rogers' Theoretical and Practical Phonetics.)

I found a phonemic inventory of Migama (Migaama) one of the Dangla (East Chadic) languages. (Also mentioned in the limerick in workshop over at Oedilf.) The inventory is not really noteworthy, but it consists of 24 consonants and 5 vowels. They are:

C:
/p,  t, -, k, ʔ/
/b,  d, -, g, -/
/ɓ,  ɗ, ʄ, -, -/
/-, ts, -, -, -/
/-, dz, -, -, -/
/-,  s, -, -, h/
/-,  z, -, -, -/
/m,  n, ɲ, ŋ, -/
/w,  l, j, -, -/
/-,  r, -, -, -/
/-,  ɽ, -, -, -/

V: /a, e, i, o, u/

(Most of the consonants, except for the third row of implosive (glottalized) stops exist in English, too.)

I've never heard of Dangla. Are the Dangla languages only spoken in Chad?