How can you tell that "barnen" is plural here?
Because of the ending -en. For neuter (ett) words, the definite form is -et in the singular (barnet) and -en in the plural (barnen). But for en-words the -en is the definite in the singular.
I had a feeling I was going to feel silly for asking that. Tack!
Why not värdefulla since it's plural children?
Is it because "tiden är värdefull" is the main part of the sentence? Thus "värdefull" corresponds to the -en ending of "tiden"?
Why couldnt it be "my children" be possible here?
Why not kids?
The TTS is utterly incomprehensible to me. Even in turtle-tongue, I cannot understand "tiden". I hear a T, but that's it. Is the TTS accurate --in which case I'm hosed for ever understanding spoken Swedish-- or does it need adjustment?