623 should be pronounced Roppyaku nijuu san.
In Japanese, numbers are often pronounced according to the On'yomi reading used when counting. In the case of 623, it is more common to pronounce it as "Roku-ni-san" (ろくにさん) instead of "Mutsumi" using the number's individual readings.
According to Wiki, this was the notable difference for Mutsumi:"Mutsumi (623) still has his radio show in the anime, but he is a student in Natsumi's class instead of a high school dropout, and his last name is Saburō (326) rather than Hojo. Also the fact that he is the host of the 623 radio show seems to be a secret from Natsumi and other listeners of the show."Not sure if that's true or not...
Huw is pronounced has 'huge' with a 'w' instead of 'ge' it IS NOT pronounced hew(he-eew)
It is spelled the same but pronounced "kryptoneat" instead of "kryptonight".
Pronounced like 'serious' but with a 'z' sound instead of 's' at the beginning.
Plural form is "parentheses", and is pronounced with an "eez" at the end instead is "is".
Pa' is the first syllable for the Spanish word "para." Pa' is used by "the younger generation". It is pronounced <pah>, or pa as shown in your question. This is analogous to American kids that say "What-ev" instead of "Whatever" or "Fav" instead of "Favorite."
The Russian word for nothing is "ничего" and it's pronounced "NEE-chee-vo". For some reason, in this word the letter "г", which would normally be pronounced as a hard "g" as in "get", is instead pronounced with a"v" sound.
The "I" in pretty much all Latin words are pronounced as an "ee" sound, instead of an "ai" sound. So Ira is pronounced as "EE-RAH"
The Russian word for nothing is "ничего" and it's pronounced "NEE-chee-vo". For some reason, in this word the letter "г", which would normally be pronounced as a hard "g" as in "get", is instead pronounced with a"v" sound.
You say "Fieber" which is pronounced just like fever but with a B instead of the V
Krieg. Pronounced like "creek" with a g instead of a k in the end.
It is pronounced like the word, "allowing" except it begins with "pl" instead of "al".