Try solving it ;)

This riddle is really neat (not easy, but the clues really "fit"!)

I'm a ten-letter word, but when I am heard,
I have only four, not one letter more.

My first two sounds are neat; a kind of sheet,
That starts with spread, not the kind on a bed.

Of my sounds, the third is what will be heard,
alphabetically, in the middle of modus operandi.

If you want to hear more, then like the shore,
I end at the sea, that's a hint, you see.

What word am I?

HINT:
There are four letters that sound just like a word of ten
letters. The word is a title of honour given to certain
high officials.

Answer: Excellency (XLNC)

The four letters, XLNC, sound just like the ten-letter word
excellency.

The first two sounds (XL) are the name of a spreadsheet program.

If you arrange the letters in modus operandi alphabetically
(addeimNooprsu), the letter N is the middle letter. Also, modus
operandi is usually written as an abbreviation, MO, which in the
alphabet, would have an N in the middle.

The final letter (C) sounds like sea. Do you see?