Is it valid, concerning the intention for fasting, to say "I intend to fast tomorrow" upon waking just before dawn, or is what matters the intention regardless of the wording?

The Sharia day begins at the dawn, and the entire night is a valid time for the intention of fasting. So, whoever makes the intention to fast at any point during the night, that suffices him, and he is not required to renew the intention. If he makes the intention to fast and then does something that invalidates it during the night, his intention is not nullified. Uttering the intention verbally is not a condition; rather, it is that the thought of fasting tomorrow crosses a person's mind.