Which among the following involves the principle of grading and sequence?

The correct answer is Gradation.

Explanation:

In language teaching and curriculum design, the principles of selection and gradation are fundamental. Gradation is the process of simplifying and organizing the language material into a sequential order so that it becomes easy for the learner to acquire.

It involves two main aspects:
1. Grouping: Putting system components together (e.g., phonetic grouping, lexical grouping, grammatical grouping).
2. Sequencing: Determining the order in which these groups or structures are taught. This ensures that the teaching moves from simple to complex, concrete to abstract, and familiar to unfamiliar.

Let's look at the other options to understand why they do not represent this specific principle:
• Habit formation: This is a psychological principle of learning, often associated with behaviorism, where language learning is viewed as forming new habits through repetition and practice.
• Following the natural way: This refers to teaching language in the natural order of acquisition, which is listening, speaking, reading, and writing (LSRW), mirroring how a child learns their mother tongue.
• Controlled vocabulary: This is a technique of limiting the number of words introduced to a learner at a given stage, but it does not encompass the broader structural sequencing and grading of grammatical patterns or language items.

Therefore, the principle that directly involves both grading (simplifying and structuring) and sequencing (ordering) of language materials is Gradation.