Cybertronian language

It should be little surprise, given a moment's thought, that distinct Cybertronian languages exist. The Transformers did not go about speaking English or any other known Earth language long ages ago on their distant metal world. Though the records of such conversations are frequently translated for us, we should not forget that these conversations originally flowed in odd electronic syllables past strange metallic lips, or were etched by alien hands long eons before the first humans painted muddy shapes upon dark cave stone.

The Transformers cartoon
The first language used by the Transformers was likely the Quintesson language inherited from their former masters. It can be seen upon the walls of the Quintesson dimensional transporter room. It rather resembles Egyptian hieroglyphs.

Ancient Autobot was the language used by the ancient Autobot colonists that fled Cybertron in the distant past. Most modern Transformers (or at least the Decepticons) could not read it.

The controls of the Plasma Energy Chamber were labeled in Ancient Cybertronian, which Spike Witwicky did not recognize.

In contrast, the language used by the Autobots when they first awoke in 1984 was easily learned. Spike Witwicky learned to read Modern Autobot after only knowing the Transformers for a single day. (Autobots and humans could also converse freely on their first encounter, though the hows and whys aren't addressed onscreen.)

Shattered Glass
The Around Cybertron news program featured both advertisements and a news scroll at the bottom of the screen written in Autobot text.

An Autobot stellar spanner was marked CWP274 in Autobot characters.

Elsewhere, a box in the Decepticon Base was marked 'fragile' in Decepticon characters.