What is a vowel chart and how does it represent vowel sounds using tongue height and frontness/backness?

• The vertical axis of the chart indicates tongue height:
  • Vowels at the top (e.g., $i$, $u$) are high (or close) vowels, meaning the tongue is close to the roof of the mouth.
  • Vowels at the bottom (e.g., $a$, $\ae$) are low (or open) vowels, meaning the tongue is low in the mouth.
• The horizontal axis indicates tongue frontness or backness:
  • Vowels on the left (e.g., $i$, $e$, $\varepsilon$, $a$, $\ae$) are front vowels, meaning the tongue is positioned towards the front of the mouth.
  • Vowels on the right (e.g., $u$, $o$, $\supset$) are back vowels, meaning the tongue is positioned towards the back of the mouth.

The symbols shown (e.g., $i$, $u$, $e$, $o$, $\varepsilon$, $\supset$, $a$, $\ae$, $I$, $\mho$) are from the International Phonetic Alphabet (IPA), each representing a distinct vowel sound. The other written words like "mfini mfini", "Anim", and "Akiji anakukuruma" appear to be additional notes or labels, possibly in another language, related to the chart's dimensions or examples.