The Navajo language is itself of some interest: Due to its high complexity, it was used as a form of cryptography by the US military in the second world war (see codetalkers). Navajo has several difficult consonants and consonant clusters. It is tonal; vowels have high or low tone, and if long can it also rise or fall. Tone is indicated in writing by an acute accent; nasality is indicated by a mark under the vowel.
According to the 2000 census, about one third of all Native Americans in Arizona now live in either Phoenix or Tucson. As of 2000, there were over 253,000 Navajo on the tribal rolls. The reports 131,166 Navajo residing in Arizona, with 17,512 living in Maricopa County (Phoenix and vicinity).