The Hausa lexicon has been inundated by loanwords, primarily from Arabic and English but also from Kanuri, Tuareg, Fulani and, more recently, Yoruba. Gender assignment has been based both on phonological patterning, mainly the association of final /a/ with feminine gender, and on semantic patterning with prior words. Phonology has been modified primarily by greater incidence and usage of glottal stop and /h/, increased incidence of the rolled R, introduction of numerous word-final consonants, retention of /e/ and /o/ in closed syllables, the incorporation of new nouns with short final vowels, and the introduction of nouns with a final Low-Low tone pattern.