Phonology deals with the 'sound structure of words'. A strong awareness of sounds is crucial to reading because students must be able to map the graphemes (letters and letter combinations) in any written words on to the individual sounds of the spoken word for both decoding and, later, sight recognition of the word. The inability to do this - rapidly parse words into sounds in order to complete the mapping process - is at the heart of poor word-level reading. All programmes go in-depth with sounds through articulation instruction and sound awareness activities.

Knowledge of sound-symbol (or phoneme-grapheme) associations is one key to the alphabetic code, which is based on the alphabetic principle that each sound (phoneme) in a word is represented by a written symbol (grapheme). Mastery of these associations enables students to decode and spell both regular and less regular words (e.g., in the Dutch loanword yacht, the sounds /y/, /o/ and /t/ are spelled by the graphemes <y>, <ach> and <t>) respectively. Programmes train students in sound-symbol associations to the level of automaticity to facilitate accurate decoding and rapid word recognition.

Syllable awareness provides a basis for students' understanding of why words are read and spelled as they are, for example, why <o> is pronounced with a short sound in not (a 'closed' syllable), but with a long sound in no (an 'open' syllable). Knowledge of syllables is particularly important for analysing long multi-syllable words and differentiating between words such as dinner and diner. In all programmes, students learn about syllable types and more advanced readers are instructed in rules for decoding multi-syllable words.

Morphology is the other key to the code as English has a morphophonemic writing system. This means that words are spelled not just on the basis of sounds but also morphemes (meaningful units) within words, and it explains why even though the <s> at the end of dogs is pronounced /z/ and not /s/ (as it is at the end of cats), the spelling does not change; the morpheme {s} signals to a reader that a noun is in its plural form. Further, a student who misspells benefit as *benifit (or misspell as *mispell) would benefit from learning about the morphemes {bene} meaning "well" and {mis} meaning "wrong". Programmes teach students high-utility morphemes that are word parts (prefixes, suffixes, word roots), enabling them to decode, spell and understand multiple words.

Syntax deals with the structure of sentences, or grammar. These structures include phrases and clauses. Syntactic awareness aids both reading fluency and comprehension. As part of each programme, students read connected texts and are taught how to identify sentence structures and apply this knowledge to the use of appropriate phrasing when reading. Additionally, students are supported to understand complex syntax, which aids in overall text comprehension.

Semantics refers to the meaning system of language. At the word level, this involves vocabulary knowledge and awareness of word relationships such as synonymy. Deep knowledge of words involves knowing not just how words are spelled and pronounced, but also what they mean in different contexts. From an early stage, programmes promote reading for meaning through activities such as having students use newly decoded words in oral sentences and learning vocabulary words selected from reading passages.