If I wanted to say the phrase 'too expensive' in Russian. The word for 'too' is слишком. And the word for 'expensive' is 'дорогая'. Then why (according to google translate which I'm assuming is correct here) does the ending of дорогая change - and 'too expensive' is:
слишком дорого
Help would be greatly appreciated. Thanks
Russian is an inflecting language, meaning that endings change all the time for every possible reason. Russian has six cases for nouns and adjectives; on top of that, adjectives inflect for gender, number, and animateness to agree with the (explicit or presumed) noun they're describing; on top of that, Russian adjectives have a "short" or predicate form, which is basically a way of saying e.g. "is expensive" without using "is", which Russian generally omits. That makes for a total of 31 forms that a Russian adjective can take; the endings on a handful of them are identical, but that's still over twenty possible endings. So unless you're familiar with the inflection system, you need the entire sentence to know the ending.
Google Translate (despite generally being a rather perfunctory tool) gave you the best translation for "too expensive" as a standalone phrase (as in "Nah, too expensive"). Here, дорого is technically the adverb "expensively" (while it's also the neuter predicate form, which is how many Russian adverbs are formed). Дорогая is the feminine nominative singular. The default/"dictionary" form of a Russian adjective is the masculine nom. sg., which would be дорогой. Here's the complete declension on Wiktionary. The ending you need might be any of them, depending, like I said, on the exact thing you want to say.
This can be слишком дорого, слишком дорогой, слишком дорогая, слишком дорогие or очень дорого, очень дорогой, очень дорогая, очень дорогие
Just to add something to other questions. There's another word that can be used interchangeably with "слишком" in this particular case (well, actually nothing comes to my mind when I'm trying to think of example when they are not 100% synonyms) - this word is "чересчур". So, "чересчур дорогой"/"чересчур дорогая" is a valid translation as well.
example when they are not 100% synonyms Well, МАС insists on possibility of using "слишком" before numeral, like "слишком два месяца" or such (Obviously, "с лишком два месяца" is OK, but the dictionary says that joint writing is acceptable here too. Not sure why so).
The phrase, that is the full sentence, "Too expensive", in general is слишком дорого. Whereas "This is" or "It is" is missing, as well as Это. Дóрого counts as adverbe, because it is a valuation (Шелякин, §107, п.10, ч.2).
However, when it intends from the context, to a subject, say a car, that is missing in the sentence, then it is an adjective and goes with its gender. For example, when the words "The car is" are missing: слишком дорогая, or слишком дорогá because машина is missing. It can be the full or short form in this case (Шелякин, §30, п.6.3, ч.3).
Generally with Слишком дорого you are on the safe side.
When part of a sentence is missing (It is..., Это...) , it is called "incomplete sentence" in the russian grammar. (Шелякин, §99, п.2, последний абзац, by indication)
Finally a native and grammar-knowledgeable russian confirms that до́рого here is an adverb.
