Celtic language - would a gaul have understood a guy from Noricum?

The Celts left no written texts and yet we dare to say that they spoke a common language and think we know some of it?

Yes, because even today there are areas where "the Celts" have lasted longer than in the rest -- Brittany, Ireland, Wales, for example -- and if you compare their languages (that is, not English and French, but Irish, Gaelic and Breton), you come across many words that are so similar to each other, despite the geographical distance, that they must have come from ancient Celtic.

In addition, clever people have reconstructed words from some written fragments, there is even a whole "Old Celtic Dictionary" for which Heinrich Tischner has collected words from Greek and Latin texts and inscriptions. There are actually few everyday language terms in it, these were, I assume, written in Latin and Greek in the Latin and Greek texts, and only those words that were "typical of the Celts" and perhaps unfamiliar to the Greeks and Romans were reproduced "in the original". This is at least my guess why we find almost no verbs here, but many plants and animals (turnip, salmon, apple tree, crested lark ...).

I can't guarantee that this dictionary is right on all terms, but I've had a lot of fun with it when looking for inspiration for the names of my Celtic characters or places. For example, Deutschlandsberg, where I put Voccio's seat of power, used to be called Wiesenbach (meadow creek). Both parts of the word can be found in Tischner's dictionary and so Bragnreica was born. (and yes, I know that most people assume Voccio was at Magdalensberg. For my novels I liked Deutschlandsberg better and so I let Voccio wander towards Magdalensberg only late in his reign ...) Or that settlement, which actually existed at the Kulm near Weiz, but whose name is not known to us: Ardudunum in my book "Culm 27 B.C." from ardu: high and dunom: fortified village.

Some words of Celtic origin can still be found in our language today -- sometimes slightly changed through the centuries. For example, the English trousers, breeches, go back to the Celtic braccae. Our officials in office (in German "Beamte") go back to ambactos (servant, messenger), likewise probably the ambassador. Our capitalistic society also has to do with the Celts and with the fact that they once invented the scythe. With the scythe it was possible to make much more hay than with the sickle. More hay meant being able to feed more animals through the winter, feeding more animals through the winter meant more calves etc in the spring. Caput was the head of cattle. More cattle, more capital, so to speak (thus Noricum was something like the forerunner of the huge Texas cattle ranches ...).

Canna - can/tin, crama - cream, the goddess Danu, which we find in the Danube ...

My very favorite Celtic expression that we still use today is the slogan, today known from every marketing seminar and advertising. Originally, the word meant "battle cry" ...