I stumbled across this comment on using the "v" and "u" in the “linguistics” forum. My question is: what does "The Romans would not have differentiated the symbols" mean? Did Romans have only one suffix -uus? If so, why we, in the modern day, substitute the original spelling -uus to -vus? From what point in time and by whom such a decision was made?
What Sam K. is saying is that the Romans would not have differentiated the letters U and V. They're the same letter in antiquity.
So the word servus and antiquus would have been spelled SERVVS and ANTIQVVS respectively. Representation of those letters in modern editions is not even consistent, with some opting for seruus and others (rarely) servvs.
It makes more sense if you read the deleted comments, too. Sam's comment was in response to another comment confused by that answer's differentiation between -vus and -uus, which in antiquity would have been written -VVS regardless of the vocalic or consonantal nature of the letter.
Originally in Latin, the letter "v" was written to show the vowel /u/ and its corresponding semivowel, /w/. The Romans did not have the sound "v" that we know in English. The Latin alphabet didn't need a letter for that sound until it started being used by the Romance languages, the Germanic languages, and other languages that had a "v" sound and a "u" sound at the same time.
"u" was a variation of the letter "v". Eventually, these became used as separate letters, which was far after the Romans.
The actual evolution of the Latin alphabet is much more complex than I'm describing it as. Every people had to modify it to suit their language, with all sorts of different sounds and sound changes happening. Regardless, the Romans only had one letter, u, which was written as v.