As my readers pointed out in their comments, the voice of Jamyra (Jamila) which sounded like groaning was also very much impressive that helped to make us aware of the tragic monster’s hostility to the human race and his grief.
When he was defeated by Ultraman with Ultra Water Stream, he roared like a crying baby crawling and wriggling in mud before he breathed his last…
Akio Jissoji who produced this episode as the director said in his book that he aimed at the effect of the monster’s voice turning into a human baby’s cry with the use of the processed voice of a real baby recorded when a crew member in charge of sound effects made his own baby cry for real (poor baby…).
Jissoji seems to find the result satisfactory enough saying he feels proud that he got to express jamyra’s innocent emotions and sadness of being wiped off from Earth.
There were cases in which a voice of a kaiju was diverted to another one like Gyango (Gango) and Telesdon (I love their voices) or came from the other monsters of films, but I think they made the sounds distinctive by processing them or overlapping sounds with each other.
Alongside of Jamyra, I think the roars of kaijus featured in the primary Ultra Series were excellently attractive and impressive to the extent that we can associate each monster with the roar he made with Alien Baltan and Zetton as typical examples.
It is also well known that the funny sounds Gavadon (A) makes when moving forward were generated from rubbing a glass surface as they apparently sound as such.