Questions & Answers about Je älter das Kind wird, umso klüger ist es.
Why is the verb at the end of the first part, but right after umso klüger in the second part?
The je part of the sentence acts like a subordinate clause, which kicks the verb (wird) to the very end. The umso part acts as the main clause. Because umso klüger takes up the first position in this main clause, the verb (ist) must come immediately after it in the second position, followed by the subject (es).
Could I use desto instead of umso here?
Yes, absolutely! je ... umso and je ... desto mean exactly the same thing and are completely interchangeable. You could just as easily say Je älter das Kind wird, desto klüger ist es.
Why does the sentence end with es instead of a gendered pronoun for the child?
The pronoun es refers back to das Kind. Because Kind is a grammatically neuter noun, you must use the neuter pronoun es, even though you are talking about a person.
Why do älter and klüger both have an umlaut here?