Letter Y can be so tricky for our students because it makes so many different sounds. It's the only letter in our alphabet that acts as both a vowel and a consonant (some teachers will also say the letter W can act as a vowel too, but it can never act as a vowel on its own - it can only pair with other vowels to become a vowel team...anyway we digress).
Back to Letter Y - as a consonant it says /y/ as in yellow, but as a vowel it can have a number of sounds depending on how many syllables are in the word and the type of syllable. Usually we see letter Y acting as a vowel in open syllable words in other words, the Y is at the end of the word.
At the end of short words (one syllable) the letter Y will say I as in cry, shy, sky, fly. At the end of longer words (two syllables or more) the Y will say E as in baby, gravy, shaky. Y can also say /i/ as in gym when it's found in the middle of a closed syllable word but we usually don't teach that explicitly until much later on.
Because this is a tricky concept for our students we have a few different ways to help them remember:
Letter Y the Robber Guy, Steals the Sounds of E & I
We have a fun free resource using this term over at TPT if you want to grab that.
We also use the Key Phrase:
To help them remember that Y says I in short words and E in multi-syllable words. We have this fun cry baby activity and word sort that WE LOVE that you can use to help support your students through this tricky lesson. You can make this more advanced by using the phrase "Cry Baby in the Gym" if you want to teach the vowel short sound of Y.
So all that to say, Y is HARD! It has 4 sounds including 1 consonant sound and 3 vowel sounds! Good luck - let us know if you need any other strategies for this one!