Tardes and Noches Edit
In English, "afternoon" comes before "evening," which in turn comes before "night." In Spanish there are only two words that cover these times of the day: "tarde" which means "afternoon," but overlaps with "evening," and "noche," which means "night" but also overlaps with "evening." Therefore, at 6:30pm it is ok to say either "buenas tardes" or "buenas noches."
Buenos Días Edit
Even though "buenos días" literally means "good days," it is used in the mornings to mean "good morning."
Conjugation of 'Hablar' Edit
Present indicative (presente del indicativo):
In Spanish, the most common negative word is "no". As an adverb negating a sentence, it always comes immediately before the verb.
I speak - [Yo] hablo.
I do not speak - [Yo] no hablo.
He is - [Él] es / está.
He is not - [Él] no es / está.