adding Hebrew text with English

when i try to publish these hebrew letters in WP it changes the hebrew letter into question marks (? ??)
do i need to add a plugin to make Hebrew letters show on the page?
link to page http://www.hebrew-lessons.com/beginner-hebrew/hebrew-alphabet-alef-bet

example:
as i past this I can see hebrew letters for the alphabet but not sure if it wipp post this way but in Microsoft word the letters save fine in a document but not on my wp site
?   alef (', a)
sometimes used as the letter a when rendering English in Hebrew
? ??   bet, vet (b, v)
with a dot like big; without a dot like move
?   gimel (g)
like go
?   dalet (d)
like dark

thanks
Kenny