Teachers using contextual instruction occasionally stop students as they read through a passage and point out certain phonetic connections such as a "ph" sounding like an "f" or the difference between long "i" and short "i." This strategy focuses on showing the students an actual phonetic rule in practice, rather than having the students repeat the sound in various words such as in a list of spelling words.
This strategy relies on the student having a basic introduction to phonics previously. Teachers have the student read the passage and pause to sound out the individual parts of the words--such as "ch" or "oo"--and put the parts together in a way that forms a word. Rather than introduce the sound through an arbitrary language arts lesson or worksheet, the teacher introduces the sound as it comes up within the reading.
This strategy encompasses building on words the student already knows. Most often this is done by comparing new words and new sounds to words or sounds the child has already mastered. "Truck" is similar and rhymes with "buck" or "duck." "Light" has the same combination of letters as "high." This relies on the children being able to memorize a large vocabulary and intuitively put the new sounds together with the already mastered sounds.
This technique puts the phonic sounds together like parts of a puzzle. The word "September" would be divided into sound combinations such as "sep," "te" (with a short "e" sound), "mb" and "er" to form the whole word. Students would take the entire word and deconstruct it on a worksheet, and possibly be required to write other words that contain the same sound combinations.