Is the Sinhalese language very different to Pali?

I notice many Sinhalese posting on Western chatsites about Buddhism. However, I often notice these Sinhalese don't have particularly strong empathy with the Pali of the suttas. I sometimes feel "dukkha" ("suffering") when having to answer their questions. Is the Sinhalese language very different to Pali? Should Sinhalese be able to learn Pali easier than Westerners?