The spelling of the word "Allelniah" can be confusing due to its unusual combination of letters. However, its pronunciation can be best explained using the International Phonetic Alphabet (IPA). IPA transcription for "Allelniah" is /æləlˈnaɪə/. This word is composed of four syllables, with the first syllable being pronounced as "al" as in "aluminum". The second and third syllables are pronounced as "luh" and "nyuh" respectively, while the final syllable is pronounced as "uh" as in "submarine".
See Halleluiah.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.