The Rihannsu Language model used on TOS TrekMUSE is based on Diane Duane's development for her books.
The sound of the language itself is supposed to be very 'soft', in syllabic terms. To Quote Diane:
"...Well, we knew, and know, very little (in the canonical sense) about Vulcan grammar. But what about the sound of the language? If the Romulans were (as I increasingly began to suspect during the writing of Enemy/Ally) an offshoot of the Vulcan culture who might equally have been thrown out, or might have left it on purpose, would they necessarily sound that much like the Vulcans any more? Mightn't it be possible that they had extensively retooled their own language to emphasize the difference between them and their parent stock? ...And if there's anything we know about the Vulcan language, it's its harshness: full of fricatives and other sharp sounds. So there at least was a hint. I wanted the Latinate sound, all right, but also intended to suggest that the Romulans / Rihannsu-to-be had purposely gone for a more melodious-sounding language, as a reaction against the hard sounds of Vulcan. So I thought that the language should be strong on liquid combinations and soft diphthongs. Welsh suggested itself to me as an example, right away: so did some of the vocalic ingredients in Greek."
Instead of spewing out how the language was developed, here's a link to the source, Diane Duane herself:
Included in that page is the Rihannsu Language Word generator, a very nifty tool that has been integrated into TOS, accessible by Romulans. Granted, it spews out a lot of impossible combinations, but if you look hard enough, it's a great idea source for names.