Giratina - \ˌjiɹəˈtinə\ (\ˌgiɹəˈtinə\ is official)
Lugia - \ˈluˈgiə\ (\ˈlugiˌə\ is official)
If possible, use the IPA when listing your pronunciations (For example, Arceus = \ˈɑɹsiəs\ is the way I do it). Otherwise, if you cba or think I'm just being pedantic, just give an approximate key (for example, Arceus = are-see-us is the way I do it.) Or, just say you mispronounce the word and be done with it.
So, the approximate keys (all caps = stressed):
Arceus - ARE-see-us (ARK-key-us is official)
Giartina - _jeer-a-TI-na (_gear-a-TI-na is official)
Lugia - LU-GI-a (LU-gi-a is official)
ncG1vNJzZmiapaGvorPAq5uepl6jsrV706GpnpmUqHy4tMicn2amkaKytHnDqGSyp6VivbO7zaisp5uVYrGqssWeqZ6mpKHGbrLRqKRmrJiaerCyxaKaopmcYsSixY1waW9uaGS9orPEZm8%3D