Why can a single Eskimo-Aleut word express an idea that needs a full English sentence?

Eskimo-Aleut languages, particularly the Inuit languages, are classified as polysynthetic. This means they are highly synthetic languages that express complex syntactic relations by clustering a large number of morphemes into a single word, typically a verb form.1

In these languages, a single word can incorporate numerous suffixes that specify modal relations, tense, and other grammatical information that would otherwise require a full sentence in English. For example, a complex Inupiaq derivative form can convey an entire thought—such as "he said that he would not be able to arrive first"—by stringing together specific derivational suffixes that correspond to each part of that English sentence.2