Secret Tongue: Tech is what the Mechanicus spoke in DH; in RT they added Speak Language: Techna-Lingua, which is the correct name for the AM's language. These seem identical and redundant to me, am I missing something?

Cheers

DH and RT are two different game systems, so whatever is listed in one does not have to be compatible to the other.

That being said, if you want , you could incorporate the Secret Tongue as an auxiliary language. After all, Secret Tongue means a cipher language whose knowledge would be more limited than a more general normal language. In this context, "Secret Tongue: Tech" could be a means of coded communication reserved for Tech-Priests of Magos rank and above, whereas Speak Language: Techna-Lingua can also be understood by lower-ranking servants, Tech-Guard grunts, Servitors and other simple machinery.

You could even specialise it further by declaring "Secret Tongue: Tech" to be a specially encoded version of Speak Language: Techna-Lingua, which will differ between various circles and factions of Tech-Priests, much like Guardsmen in DH can buy a military sign language Skill which would, of course, also differ from regiment to regiment, depending on the homeworld and its army traditions.

which is the correct name for the AM's language

Of course that is relative in a setting that does not actually have a uniform canon and embraces contradictions.

I raised the point because both are already listed in the RT Skills section.

I could house-rule it in a number of different ways, yeah, but I wondered if there was some sort of consensus.

Maybe Techna-Lingua doesn't require extra bits to understand? In Star Wars, some people, like Luke Skywalker, could understand what R2-D2 was saying, which I always found to be BS. He's a droid, so no Force-cheese is really helping Luke translate four beeps into three paragraphs of technical lingo, but he can hear it; R2 "speaks" in an audible range that anyone who can hear can hear. The other one, Tech, describes itself as using certain low and high-frequency sound waves, sort of like elephants with ultrasound, perhaps, that they can hear, but we can, maybe, only feel. Such a language might require that you have augmented hearing devices, which Tech-Priests, more than likely, would get, but the rest of us, not so likely.

Thus, TL might be a plainly audible language, for humans (that, being binary, we probably shouldn't be able to understand, do to info compression, or that should take forever to speak with), while SC: tech might be a more in-depth variant of that, but also require additional accoutrements to understand, and communicate back. Here's hoping I didn't just make all that crap up.

That's a brilliant explanation, thankyou. Every one I came up with either changed something fundamental or I could argue myself out of but that makes perfect sense.

I raised the point because both are already listed in the RT Skills section.

Ah, gotcha - the initial mention of DH trew me off. Sorry!