These words are Pig Latin, which is a language game in English. It means "Christmas Spirit." You take the first sounds of an english word, put them at the end, and add "ay," like this:

christmas - istmas-chr-ay - istmaschray

spirit - irit-sp-ay - iritspay

A different example:

potato - otato-p-ay - otatopay

This is just a silly joke though, it's very interesting but its not commonly used.

It's Pig Latin. This is a word game which children sometimes play to amuse themselves and stop people understanding them. When people are speaking in Pig Latin, it sounds like a foreign language. But in fact, all the speakers are doing is swapping around some sounds in each word and adding a syllable or two.

In this version of the game, you take off the first letters of the word and put them at the end of the word, followed by 'ay'.

Istmas - chray = Christmas

irit-spay   = spirit