I see it happen all the time. Nope, they’re not typos. They’re misused words. They may sound alike, but they are nothing alike.
Here are the most common ones I’ve seen:
farther and further: Farther refers to distance; further refers to extent or degree
lie and lay: In the present tense, lie means to rest; lay means to put or to place
foreword and forward: Foreword is a noun that means an introductory note or preface; Forward is an adjective or adverb that means toward the front:
it’s and its: It’s is a contraction for it is; its is the possessive form of it
past and passed: Passed functions as a verb; past functions as a noun, adjective, or preposition
than and then: Than is a conjunction used in making comparisons; then is an adverb indicating time
their, they’re and there: Their is the possessive form of they; there refers to place; and they’re is the contraction of they are.
your and you’re: Your is the possessive form of you; you’re is the contraction you are
There are also misused words that don’t sound alike:
each other and one another: Each other is used to refer to two people; one another is used to refer to more than two people.
number and amount: Use number to things that can be counted; use amount for things that cannot be counted.
Don’t forget to check your emails and manuscripts for misused words before sending them out.