Learn Icelandic: Hvernig læra þau tungumálið? - How do they learn the language?

In Icelandic questions that start with a question word, the verb always swaps places with the subject. Since hvernig takes the first position, the verb læra must take the second position, pushing the subject þau into the third position.

Why use þau for "they" instead of þeir or þær?

Þau is the neuter plural form of "they". In Icelandic, if you are talking about a mixed group of males and females, or if you simply do not know the genders of the people in the group, you always default to the neuter form þau.

Where is the word for "the" in tungumálið?

Instead of using a separate word for "the" before the noun, Icelandic attaches a suffix to the end of the word. The base word is tungumál (language), and the neuter suffix -ið is added to make it tungumálið (the language).