1. say [sei]

2. says[sez]
3. says [seiz]
----------------------------
#1 and #2 are correct. What about #3? Don't you use the pronunciation of #3? How come you don't use #3?

There's no answer for why pronunciation #3 is not used. That's just the way it is!

Here are other strange pronunciations for you -- and there's no explaining them. They just are the way they are!

The bandage was wound around the wound.
The farm was used to produce produce.
The dump was so full that it had to refuse more refuse.
We must polish the Polish furniture.
He could lead if he would get the lead out.
The soldier decided to desert his dessert in the desert.
Since there is no time like the present, he thought it was time to present the present.
A bass was painted on the head of the bass drum.
When shot at, the dove dove into the bushes.
I did not object to the object.
The insurance was invalid for the invalid.
There was a row among the oarsmen about how to row.
They were too close to the door to close it.
The buck does funny things when the does are present.
A seamstress and a sewer fell down into a sewer line.
To help with planting, the farmer taught his sow to sow.
The wind was too strong to wind the sail.
Upon seeing the tear in the painting, I shed a tear.
I had to subject the subject to a series of tests.
How can I intimate this to my most intimate friend?
http://www.memphisdyslexia.org/articles/english.pdf

In order to accurately explain why we don't use the pronunciation for #3, I'll break it down for you.

When it comes to pronouncing words, it's important to understand the variations in different dialects and accents. In the case of the word "says," there are different pronunciations that can be considered correct depending on the regional accent or dialect. However, for standard English, pronunciations #1 and #2 are generally accepted.

Pronunciation #3, where "says" is pronounced as [seiz], can be found in some dialects or accents such as certain regions within the United States. It's important to note that while this pronunciation variation exists, it is not considered the standard pronunciation in most English-speaking regions.

As an AI language model, I generally provide information based on standard pronunciations and widely accepted usage. That's why I don't emphasize pronunciation #3 for "says" unless specified or indicated by the user. However, it's always important to be aware of the various regional dialects and accents that may utilize different pronunciations for words.