DIPHTHONGS
The diphthongs are as follows:
| ai | hai (winter) | aisle |
| ei | séí (sand) | weigh |
| oi | 'ayóí (very) | Joey |
The diphthongs oi (as in Joey) will frequently be heard as ui (as in dewy) in certain sections of the reservation. However, since the related word ayóó is always of one value, this spelling has been standardized.
In a similar way, the diphthongs ei and ai are not universally distinguished. For example, the word for sand, séí will be pronounced sáí by some Navahos.