Quenya 

ala-

not

ala- (2) negative prefix "not", "un-", reduced to al- before a vowel (VT42:33, GALA, VT45:25), though the example Alcorin would suggest that al- can sometimes appear before a consonant as well. In a deleted entry in Etym, al(a)- was defined as "not" and said to be a "pure negative" (VT45:5). In alahasta, Alamanyar, alasaila, Alcorin.