Learn Hardcore Turkish: Turuncu, pembe, mor ve sarı şemsiyeler kumsalı renklendiriyor. - Orange, pink, purple and yellow umbrellas color the beach.

In Turkish, adjectives never inflect for number or case—they remain exactly the same whether the noun is singular or plural. Only the noun itself takes the plural suffix (-ler/-lar).
• şemsiye (umbrella) → şemsiyeler (umbrellas)
• kırmızı arabalar (red cars), not kırmızılar arabalar

What does the -ı in kumsalı do? Why isn’t it just kumsal?

That -ı is the 3rd-person singular accusative suffix, marking kumsal (“beach”) as a definite direct object (“the beach”).
• kumsal = “a beach” (indefinite, unmarked)
• kumsalı = “the beach” (definite, accusative)

Why is the verb renklendiriyor at the very end of the sentence?

Turkish has a basic Subject-Object-Verb (SOV) word order. Here you see:
1) Subject = şemsiyeler
2) Object = kumsalı
3) Verb = renklendiriyor (“is coloring”)

How is the verb renklendiriyor constructed? What are its parts?

Breakdown of renklendiriyor (“is coloring”):
1) renk – noun root “color”
2) -lendir – causative suffix “cause to be X” → “to color”
3) -iyor – present-continuous suffix “is …ing”
Altogether: renk + -lendir + -iyor = “(he/she/it) is coloring”

How do we know who is doing the coloring? There’s no separate subject pronoun.

In Turkish, the absence of a personal suffix after the tense/aspect marker indicates 3rd-person singular. Other persons use:
• -yorum (I …)
• -yorsun (you …)
• -yoruz (we …)
etc.
Here renklendiriyor = “he/she/it is coloring.”

Why aren’t there any words for “the” or “a” in this sentence?

Turkish has no independent articles. Indefiniteness is unmarked (zero article), while definiteness is shown by the accusative suffix (-ı/-i/-u/-ü). E.g.:
• kedi = “a cat” (indefinite)
• kediyi = “the cat” (definite, accusative)

How does Turkish vowel harmony decide between -ler/-lar and -ı/-i/-u/-ü in suffixes?

Suffix vowels harmonize with the last vowel of the stem:
• şemsiye ends in i (front unrounded) → plural suffix is -ler → şemsiyeler
• kumsal ends in a (back unrounded) → accusative is -ı → kumsalı

I notice there’s no comma before ve. In English we sometimes use an Oxford comma; what about Turkish?

In Turkish punctuation, you do not put a comma before the final ve in a list. The standard form is:
A, B, C ve D
never A, B, C, *ve D*.