The best sentences for building a useful speech recognition engine are colloquial, modern parlance. Some ideas to help you generate sentences are;
ⵜⵉⵡⵉⵏⴰⵙ ⵜⵉⵎⵓⴼⴰⵢⵉⵏ ⵉ ⵓⵥⴽⴽⵓ ⵏ ⵢⴰⵏ ⵓⵏⵙⵎⴰⵙⵙⵓ ⵓⵏⴼⵓⵜ ⵏ ⵜⵓⴽⵣⴰ ⵏ ⵡⴰⵡⴰⵍ ⵍⴰ ⵜⵜⴳⴳⴰⵏⵜ ⵜⵓⵏⵏⵉⵎⵉⵏ, ⵙⴳ ⵡⴰⵡⴰⵍ ⴰⵜⵔⴰⵔ. ⵀⴰ ⴽⵔⴰ ⵏ ⵜⵡⵏⴳⵉⵎⵉⵏ ⵏⵏⴰ ⵔⴰⴷ ⴰⵡⵏ ⵢⴰⵡⵙ ⴰⴷ ⵜⴰⵔⵡⵎ ⵜⵉⵡⵉⵏⴰⵙ: