Ahsoka says within "Chapter 13: The Jedi" that he's the same species (or type of "being"):
Then his memory becomes... dark. He seemed lost. Alone. I've only known one other being like this. A wise Jedi Master named Yoda.
(Source: The Mandalorian, Chapter 13: The Jedi, via https://transcripts.foreverdreaming.org/viewtopic.php?t=40521)
(It makes sense that she wouldn't have known Yaddle, who died in 32 BBY when Ahsoka was 4 years old).