WIDA's Performance Descriptions (right) both include linguistic complexity and language forms. Therefore, strong ELD lessons should push intermediate language learners not only to greater vocabulary sophistication, but also to more complex and accurate language structure.
Language forms should be aligned with the lesson's communicative task and grade-level standards. They should be modeled by the teacher and present in the receptive language portion of the lesson. A practice opportunity is essential to making this a good use of class time.
Selecting a structure to teach
In order to determine what language form would be appropriate for your lesson, first think about the communicative task and the type of sentences and syntax it requires. Then, I recommend consulting the LAUSD Functions and Forms (has sentence frames) and/or the language progressions aligned with CCSS by Eastern Suffolk BOCES. Choose one language structure that is appropriate developmentally, aligned with your language goal, and pushes your students toward the next level of complexity.
Alternately, you may want to address an area of need you have noticed. For example, many ELLs struggle with when to add s to the end of third person verbs (I walk vs. he walks). Irregular plural nouns and past tense verb forms can also be challenging. If you notice a pattern in your students' errors, consider creating a language structure lesson to help them increase accuracy.
A third possibility is clarifying the grammatical differences between your students' L1 and L2. See the table below for a few contrasting features of Arabic and Spanish syntax when compared to English. There are many others, including alphabetic, phonetic, and morphological differences. I encourage you to research and learn more about the first languages of your students!
Designing activities
There is much to learn and think about when structuring activities that promote the acquisition of accurate and/or complex language structures. The NCLRC (National Capitol Language Resource Center) recommends the following sequence for teaching grammar points:
1) structured input -- students hear and/or see the language structure in a comprehensible context
2) short explanation by teacher/grammar deduction by students
3) structured output --students do an activity that provides supported practice producing the new structure
4) application in a communicative context -- students use the structure to complete a communicative task
You may notice that this aligns exactly with the ELD Focus Time template.
A small sampling of grammatical differences: