Teaching Complex Sentences in Speech Therapy

Complex sentence skills help students explain why something happened, describe when events occur, compare ideas, and communicate conditions or unexpected outcomes. These skills are important for classroom discussions, academic language, writing, and everyday conversations.

Here are five functional activities and ready-to-use prompts for teaching complex sentences in speech therapy—no elaborate materials needed!

How to Teach Complex Sentences

Start by helping students understand how two ideas can fit together in one sentence. A complex sentence contains a main clause and at least one dependent clause that adds information.

For example:

• Two simple sentences: “I stayed home. I was sick.”
• Complex sentence: “I stayed home because I was sick.”

The second sentence explains the relationship between the ideas instead of simply listing what happened.

A Simple Teaching Approach

1. Model: Demonstrate how to connect two related ideas using a target conjunction or clause structure.
2. Practice together: Provide two simple sentences and help students combine them.
3. Generate: Give a familiar situation and have students create their own sentence.
4. Apply: Use the target structure in a conversation, classroom explanation, or everyday situation.

Quick Reference: What Should I Target?

Language Goal	Target Words	Example
Explain why	because, since	I asked for help because I didn’t understand the directions.
Explain when	before, after, when, while	We cleaned up after the game ended.
Describe conditions	if, unless	If it rains, we’ll eat lunch inside.
Express contrast	although, even though	Although I was nervous, I gave my presentation.
Add identifying details	who, that, which	The student who found my notebook returned it.

5 Functional Complex Sentence Activities for Speech Therapy

These activities can be completed orally or in writing and adapted for different ages and language levels.

1. Explain Your Reason: Because & Since

Use everyday decisions and experiences to help students explain why something happened or why they made a particular choice.

Example:

“I brought an umbrella. The weather forecast predicted rain.” → “I brought an umbrella because the forecast predicted rain.”

Try These Prompts:

• Explain why you might ask a teacher for help.
• Tell me why someone might choose to walk instead of drive.
• Describe something you did today and explain why you did it.

Extend It: Have students provide more than one reason or move the dependent clause to the beginning: “Because the forecast predicted rain, I brought an umbrella.”

Need more support? Provide two related statements and a sentence starter such as “I ___ because ___.” Model the relationship before asking students to generate their own examples.

2. Tell Me When: Before, After & While

Practice explaining routines, events, and instructions using time relationships. This is especially useful for classroom participation and everyday independence.

Example:

“The bell rang. We packed our bags.” → “After the bell rang, we packed our bags.”

Try These Prompts:

• Explain what you do before leaving for school.
• Describe something you do after finishing an assignment.
• Tell me two things that might happen at the same time.

Extend It: Change the conjunction and discuss how the meaning changes. For example, compare “I washed my hands before I ate” with “I washed my hands after I ate.”

Need more support? Use two picture cues or act out the events. Have students identify the order before combining the ideas.

Free Resource: Use the Free Following Directions Activities for additional practice with temporal, sequential, and conditional language.

3. Make a Plan: If & Unless

Conditional sentences help students explain what could happen under different circumstances. They are particularly useful for planning, decision-making, and understanding classroom expectations.

Example:

“The printer might stop working. I can submit my assignment online.” → “If the printer stops working, I can submit my assignment online.”

Try These Prompts:

• What will you do if you forget your homework?
• What could you do if your first plan doesn’t work?
• What will happen if you finish your work early?

Extend It: Introduce unless and compare its meaning with if. For example: “We’ll play outside unless it rains.” Have students explain what would happen if it did rain.

Need more support? Present a simple situation and offer two possible outcomes. Provide an “If ___, then ___” sentence frame before moving to independent responses.

4. Compare Ideas: Although & Even Though

Help students explain contrasts, surprising outcomes, and situations where two ideas seem to conflict.

Example:

“The bus was crowded. I found a seat.” → “Although the bus was crowded, I found a seat.”

Try These Prompts:

• Describe something you enjoyed even though it was difficult.
• Explain why you might choose one activity although another is easier.
• Tell me about a time something happened despite an obstacle.

Extend It: Compare sentences using because and although. Discuss how changing the conjunction changes the meaning.

For example:

• “I stayed inside because it was raining.”
• “I went outside although it was raining.”

Need more support? Begin with familiar situations where the contrast is obvious. Model a complete sentence before having students create their own.

Free Resource: Use my 100 Free Compare and Contrast Prompts to generate topics for practicing contrastive sentences.

5. Add Important Details: Who, That & Which

Relative clauses help students identify people, objects, or places more precisely. They’re useful when giving directions, describing items, or explaining which person or thing they’re talking about.

Example:

“The girl is my classmate. She sits near the window.” → “The girl who sits near the window is my classmate.”

Try These Prompts:

• Describe a person who helped you recently.
• Explain which book, game, or movie you’re talking about.
• Give directions to find a specific object in the room.

Extend It: Have students combine two sentences using who, that, or which. Then ask them to create a new sentence without a model.

For example: “Please hand me the notebook that has the green sticker.”

Need more support? Place two similar objects in front of the student. Model how an added clause identifies the correct item: “Give me the pencil that has an eraser.”

A Quick 5-Minute Complex Sentence Activity

Short on time? Try this simple routine during a session:

1. Model one sentence: Demonstrate the target structure and explain what it means.
2. Combine two ideas: Give students two related sentences and a target conjunction.
3. Generate a sentence: Present a familiar situation and have students create their own example.
4. Change the meaning: Switch the conjunction, rearrange the clauses, or add a new condition.
5. Apply it: Ask a conversational question that encourages the student to use the structure naturally.

For mixed groups, everyone can respond to the same scenario while working on a different structure or level of complexity.

Make Complex Sentences Functional

Teaching complex sentences isn’t about making students use longer words or speak in unnecessarily complicated ways. It’s about helping them express relationships between ideas clearly and effectively.

Start with familiar situations and model the target structure. As students improve, move beyond structured sentence-combining tasks. Have them explain decisions, describe routines, give instructions, or discuss everyday situations using more complex language.

For more functional practice, explore my Free Speech Therapy Activities, including following directions, compare and contrast, and problem-solving prompts that can easily be adapted for sentence formulation.

Research Spotlight: Balthazar and Scott (2024) emphasize the importance of teaching complex sentences within meaningful academic and communication activities. Their article, Sentences Are Key: Helping School-Age Children and Adolescents Build Sentence Skills Needed for Real Language, offers practical strategies for targeting complex syntax, including modeling, sentence combining, and explicit instruction.