[dragonwriter]

> I put the stress differently, but otherwise I would pronounce Alexa as Alexander cut short.

In “Alexander”, the normal pronunciation of the letter “x” is the voiced consonant cluster /gz/, in “Alexa”, it's usually the unvoiced cluster /ks/. (Also, the second “a” is usually different between the two, being /æ/, like the “a” in “pad”, in “Alexander” and /ɑ:/, like the “a” in “father”, in “Alexa”.)

The difference in the “x” is the normal way that the pronunciation of “x” differs when following a stressed vs. unstressed vowel in English.