So, Too, Neither & Either

What Are So, Too, Neither & Either?

When someone tells you something about themselves and you feel the same way, English gives you four elegant little words to express agreement: so, too, neither, and either. These words are used to show that a statement applies to another person or thing as well. Instead of repeating an entire sentence, you can use these short structures to say "the same is true for me" in just a few words. They are among the most frequently used conversational tools in everyday English.

So and too are used to agree with affirmative (positive) statements. If someone says "I love coffee," you can respond with "So do I" or "I do too." Both mean exactly the same thing — that you also love coffee. Neither and either work the same way, but they are used to agree with negative statements. If someone says "I do not like spiders," you can say "Neither do I" or "I do not either."

These structures are essential for natural conversation. Without them, you would need to repeat the full sentence every time you agree, which sounds awkward and unnatural. Mastering so, too, neither, and either allows you to respond quickly, sound fluent, and keep conversations flowing smoothly.

When Do We Use Them?

We use so, too, neither, and either in conversations when we want to express that we share the same experience, opinion, ability, or situation as another person. They appear constantly in daily English — at school, at work, among friends, and in formal settings. Understanding when to use each one depends on whether the original statement is positive or negative.

So + Auxiliary + Subject — Agreeing with Affirmative

The structure So + auxiliary + subject is used to agree with a positive statement. It is the most common way to express affirmative agreement in English. The word order is inverted — the auxiliary verb comes before the subject, just like in a question. The auxiliary must match the tense and verb type of the original statement.

Neither + Auxiliary + Subject — Agreeing with Negative

The structure Neither + auxiliary + subject is the negative counterpart of "So + auxiliary + subject." It is used to agree with a negative statement. Just like with "so," the word order is inverted — the auxiliary comes before the subject. Importantly, the auxiliary verb in the response is not negative, because "neither" already carries the negative meaning.

Too and Either — Alternative Forms

Too and either offer alternative ways to express agreement. Unlike "so" and "neither," they come at the end of the sentence, and the word order is normal (not inverted). Too is used with positive statements, and either is used with negative statements. Many learners find these forms easier because the sentence structure is more straightforward.

Choosing the Right Auxiliary

The trickiest part of using so, too, neither, and either is selecting the correct auxiliary verb. The auxiliary in your response must match the tense and verb type used in the original statement. If the original sentence uses "be," your response uses "be." If the original uses a modal verb like "can" or "will," your response must use the same modal. For simple tenses without a visible auxiliary, you use "do/does/did."

Example Sentences

So/Neither with Different Tenses

One of the biggest challenges with these structures is using them correctly across all English tenses. Below is a comprehensive reference showing how so and neither work with every major tense. Study these examples carefully and notice how the auxiliary changes for each tense while the basic pattern stays the same.

Common Mistakes

Even advanced learners make mistakes with these agreement structures. Below are the most frequent errors, along with clear explanations of why they are wrong and how to fix them. Study each one carefully to avoid these pitfalls in your own speaking and writing.

So/Too vs. Neither/Either — Complete Comparison

Now that we have studied all four structures in detail, let us put them side by side in a comprehensive comparison. This table will help you see the patterns clearly and choose the right structure for any situation.