ah-BOO-eh-lah
* ah: Like the "a" in "father"
* BOO: Like the word "boo"
* eh: Like the "e" in "bet"
* lah: Like the word "la"
It's important to note that the "u" in "abuela" is pronounced like the "u" in "flute" or "rule," not like the "u" in "put" or "cup."