Learn Hardcore Russian: Сладкая газировка вредная для здоровья.

Russian normally drops the present-tense “to be.” So you say Сладкая газировка вредная для здоровья without a verb. In the past/future you use it: Газировка была/будет вредна для здоровья. Using есть here sounds unnatural.

Why do both сладкая and вредная end in -ая?

They agree with the noun газировка, which is feminine, singular, nominative. Full adjectives take -ая in that slot: сладкая газировка, газировка вредная.

Why вредная and not вредна or вредно?

вредная = full adjective agreeing with the subject; perfectly correct.
вредна = short-form feminine; also correct and a bit more concise: Сладкая газировка вредна для здоровья.
вредно (neuter) is impersonal; use it when there’s no noun subject, typically with an infinitive: Пить сладкую газировку вредно. Don’t use вредно with a specific noun subject.

What case is для здоровья, and why not для здоровье?

для requires the genitive case. здоро́вье (nom.) → здоро́вья (gen.). Hence для здоровья.

Can I say Сладкая газировка вредна здоровью?

Yes. With the short form (вреден/вредна/вредно), Russian often uses the dative: Газировка вредна здоровью. It means the same as вредна для здоровья and sounds succinct.

Is газировка the normal word for “soda/pop”? Is сода okay?

Газировка is the everyday word for soda/soft drinks. Сода in Russian usually means baking soda; for club soda you’d hear содовая. More formal/explicit options: газированная вода (carbonated water), газированный напиток (carbonated drink).

Is газировка countable?

It can be both:

Countable: две газировки (“two sodas”).
Mass/generic: Я не пью газировку (“I don’t drink soda”).

Where are the articles “a/the”? How do I know if it’s general or specific?

Russian has no articles. Context decides. As written, it’s a general statement. You can reinforce generality with plural/impersonal patterns: Сладкие газировки вредны для здоровья; Пить сладкую газировку вредно.

Could I use a dash: Газировка — вредна для здоровья?

Yes. A dash before the predicate adjective is a common stylistic choice for clarity/emphasis. Without the dash is also correct.

Can I change the word order for emphasis?

Yes, within limits. Fronting the predicate for emphasis is possible: Вредна для здоровья сладкая газировка (emphasizes “harmful”). But Газировка сладкая вредная… sounds awkward here; keep adjectives either attributive before the noun or in the predicate.

How would I say it in the plural?

Сладкие газировки вредны для здоровья. Adjective and predicate agree in plural: сладкие … вредны.

Why сладкая and not сахарная?

Сладкий means “sweet-tasting,” which is what you want. Сахарный literally means “made of/containing sugar” and is used for things like сахарная свёкла (sugar beet); for drinks people usually say сладкая газировка or газировка с сахаром.

Is there a verb alternative to say the same thing?

Yes: Сладкая газировка вредит здоровью. Here вредить takes the dative (здоровью).

How do I pronounce the tricky words?

Stress them as: сла́дкая, газиро́вка, вре́дная, здоро́вья. (Stress marks shown for learning; they’re not written in normal text.)