1. A comparison of vowel normalization procedures for language variation research;Adank;J. Acoust. Soc. Am.,2004
2. The KIT-split in South African English. A critical review;Bekker;Southern African Linguist. Appl. Lang. Stud.,2014
3. Boersma, Paul, Weenink, David, 2018. Praat: Doing phonetics by computer. Version 6.0.37, retrieved 14 March 2018 from http://www.praat.org.
4. Da Silva, Arista, 2007. South African English: A sociolinguistic analysis of an emerging variety. Doctoral Dissertation. University of the Witwatersrand.
5. A reference grammar of Oshindonga;Fivaz,2003