Hausa, Yoruba, Igbo

Though Guosa draws its lexicon from at least 118 indigenous West African languages, it derives the bulk of its vocabulary from Hausa, Yoruba, and Igbo, either taken directly or made from a combination of words from these languages. English also provides many of the more technical terms, either directly or through one of the aforementioned African languages. Additionally, several words were produced a priori via sound symbolism, e.g. meeh "sheep", yanmu-yanmu "mosquito", and wuam "eat".

The different parts of speech are often derived from specific languages. Most concrete nouns are derived from Hausa, while verbs and abstracts are derived from Igbo or Yoruba. Additionally, words from all three source languages are often fused to create a word that resembles all three. For example, the Guosa word méni "what" is derived from Hausa menini, Igbo gini, and Yoruba kini, all meaning "what".