Learn Finnish: Älkää unohtako näitä tärkeitä ohjeita. - Do not forget these important instructions.

To tell a group of people (or one person formally) not to do something, use the negative word älkää followed by the verb's plural connegative form. To make this form, take the dictionary form of the verb (unohtaa), remove the final vowel, and add -ko (or -kö for front-vowel words). So, unohtaa becomes unohtako.

Why does unohtako have a strong t instead of the weak d we see in the singular command älä unohda?

Plural imperatives are built using the strong grade of the verb stem, just like the dictionary form (unohtaa). Because it has a strong ht, unohtako keeps the ht. The singular imperative (älä unohda) is built from the "I" form (unohdan), which triggers consonant gradation to the weak grade hd.

Why is the object näitä tärkeitä ohjeita in the partitive plural case?

In Finnish, if a sentence is negative, its object must always be in the partitive case. Because this is a negative command (älkää means "do not"), the entire phrase "these important instructions" is put into the partitive plural.

How do we get the form ohjeita from the basic word for "instruction"?