Learn Dutch: Ik zie twaalf bomen en dertien bloemen. - I see twelve trees and thirteen flowers.

twaalf (twelve) is a unique word, just like in English. For dertien (thirteen), Dutch combines der (a form of three) and tien (ten). Many numbers from 13 to 19 follow this pattern by ending in -tien, which is exactly like the English ending "-teen".

The dictionary word for tree is boom. Why does it change to bomen here instead of boomen?

This happens because of a Dutch spelling rule for "long" vowels. When you add the plural ending -en, the word splits into syllables like this: bo-men. A single vowel at the end of a syllable automatically makes a long sound. So, the second o is dropped because it is no longer needed.

The word for flower is bloem. Why doesn't it lose a vowel in the plural like bomen did?

The word bloem uses the vowel combination oe, which makes an "oo" sound (like in the English word "boot"). Unlike the double oo in boom, special two-letter vowel combinations like oe, ie, and eu never drop a letter when a word gets longer. So, it simply becomes bloemen.

Why is the verb zie instead of the full verb zien?