Questions & Answers about Både rytmen och texten är uråldriga.
Why is the adjective uråldriga in the plural form here?
Because it describes a compound subject joined by både... och... (both... and...). Even though rytmen and texten are singular nouns, together they form a plural subject, so the predicate adjective must take the plural ending -a.
If we added an infinitive to make a 'tough-movement' sentence (like 'are ancient to sing'), would the adjective agreement change?
No, it would remain plural. If you said Både rytmen och texten är uråldriga att sjunga, the adjective uråldriga still agrees with the plural compound subject at the front of the sentence. This contrasts with using a 'dummy' subject, which forces the neuter singular form: Det är uråldrigt att sjunga både rytmen och texten.
What exactly does the prefix ur- add to the word åldriga?
The prefix ur- usually means 'original', 'primeval', or 'extremely'. While åldrig means 'aged' or 'elderly', adding ur- intensifies it to mean 'ancient'. You will also see this prefix in words like urskog (primeval forest) or ursprung (origin).