Both decoding and encoding skills are needed to build a foundation in reading. Decoding is the process of translating written speech into verbal speech sounds by applying knowledge of letter-sound correspondences. It is the ability to recognize letters, apply their associated sounds, and blend sounds to form words. Encoding is the process of using letter-sound knowledge to write or spell words. Students must understand the various spelling patterns and rules of the Spanish language to correctly construct words in their written products. It is important that students demonstrate their knowledge by applying these rules consistently instead of using invented spelling because they may unknowingly write a real word that they did not intend, causing confusion for their reader.

A hiatus refers to two adjacent vowels within a word that do not belong to the same syllable. Hiatuses may be formal or accented. A formal hiatus is composed of two strong vowels (a, e, o). For example, lí-ne-a, cre-er, al-de-a. An accented hiatus is composed of a weak vowel (i, u) and a strong vowel (a, e, o); however, the weak vowel must always have a written accent: frí-o, e-go-ís-ta, sa-bí-a, grú-a. Students are expected to understand the concept of both formal and accented hiatuses and should be able to spell them correctly.

A diphthong is a combination of a strong vowel (a,e,o) and a weak vowel (i,u) in a single syllable. For example, tie-rra, cui-da-do, fue-go, pai-sa-je. Students are expected to know that diphthongs are always in the same syllable and should be able to spell them correctly.