Learn Turkish: Nöbetçi hava soğukken üşür. - The guard gets cold when the weather is cold.

In English, we use "cold" for both the weather and the physical feeling. Turkish separates these. Soğuk is an adjective used for the temperature of objects or the weather. Üşümek is a verb meaning "to feel cold." If you said nöbetçi soğuk, it would mean the guard is physically cold to the touch!

How exactly does the suffix -ken work in soğukken?

The suffix -ken means "while" or "when." When you attach it directly to an adjective like soğuk (cold), it means "while being cold" or "when it is cold." Since soğuk ends in a consonant, we just add -ken directly to get soğukken.

Wait, shouldn't -ken follow vowel harmony? Why isn't it soğukkan?

The suffix -ken is a famous exception to the rules of Turkish vowel harmony! It never changes its vowel to match the word it attaches to. It will always remain -ken.

Why does the verb use the aorist tense (üşür) instead of the present continuous tense (üşüyor)?

The aorist or simple present tense (ending here in -ür) is used to state general facts, habits, or universal truths. This sentence isn't about a specific guard feeling cold right now; it is a general statement that guards get cold whenever the weather is cold.