Fix two bugs for blank voice (empty speech): (#1403)

jianganghan

2024-02-29 f272eb4ef78e12a1ef4ae451b114f980a2682d51

1
2
3
4
5
6
7
8
9
twenty    2
thirty    3
forty    4
fourty    4
fifty    5
sixty    6
seventy    7
eighty    8
ninety    9