Learn Spanish (Spain): Veía la tele debajo de esa mantita calentita. - I used to watch TV under that nice warm little blanket.

Adding the diminutive suffix -ita to manta (blanket) creates mantita. In this context, it does not necessarily mean the blanket is physically tiny. Instead, it adds a feeling of coziness, affection, and comfort, which translates well to the English idea of a nice little blanket.

The word for warm is caliente. Why does it become calentita instead of calientita?

In Spain, when you add a diminutive suffix to certain words with an ie vowel combination, the ie changes back to a simple e. This happens because the spoken stress of the word moves to the new -ita ending. Therefore, caliente drops its final vowel and the ie becomes an e, resulting in calentita. Using the diminutive on this adjective emphasizes a pleasant, cozy warmth.

Why is the imperfect tense (veía) used here rather than the preterite (vi)?

The imperfect tense is used to describe past habits, routines, or continuous states. The English translation says I used to watch, which indicates that this was a repeated, ongoing routine in the past. If you used the preterite form (vi), it would mean you watched TV just once from start to finish on a specific occasion.

Why do we need the preposition de after debajo?