Learn French: Est-ce que la valise est lourde ?

Literally, it translates to "Is it that". However, you shouldn't translate it word-for-word into English. In French, it is simply a handy phrase you put at the very beginning of a sentence to turn it into a yes/no question.

In English we say "Is the suitcase...". Why does the French say la valise est (the suitcase is)?

In English, we usually swap the subject and the verb to ask a question. In French, the beauty of Est-ce que is that you don't need to change the word order at all! You just take the normal statement (la valise est lourde) and place Est-ce que right in front of it.

Why does the word for heavy (lourde) end with an "e" in this sentence?

Because it is describing la valise (the suitcase), which is a feminine noun. The basic masculine word for heavy is lourd, but we must add an e to make it feminine (lourde) so it matches the noun.

Could I ask this same question without using Est-ce que?

Yes! In everyday spoken French, people often just say the regular sentence but raise their voice at the pitch at the end to make it a question: La valise est lourde ? However, Est-ce que is extremely common and clearly signals from the start that a question is coming, so it is a great structure to master.