needaTEAcher wrote:please forgive my ignorance...what do the 2 and 4 mean?
In Hanyu Pinyin hese just indicate the tones in spoken Putonghua / Mandarin.
1 = ā (high flat)
2 = á (rising)
3 = ǎ (falling-rising)
4 = à (falling)
[no diacritic] = neutral (short, de-stressed flat tone)
These are somewhat further complicated by tone sandhis, for example, when two third tones are pronounced together, the first one is pronounced like second tone, or with certain words, a 4th tone word will turn into second tone before another 4th tone).
It gets a lot harder in some other Sinitic tonal languages, where there can be 7+ tones, and more complicated interactions between the tones.