The All About Spelling program purposefully avoids technical jargon wherever possible. When an unfamiliar term (such as blends or phonograms) must be used, the term is immediately explained and examples are given. A mom using the Level One program wrote in with a question about the letter combination th. Here is her letter:

We are on Step 9 where the two sounds of th are introduced. We do have the Phonogram CD-ROM to help us out, but personally, I do not hear the difference between the two sounds when given the two different example words of three and then. Do you have any other words to give as examples of both sounds of th?

Th has two sounds: voiced and unvoiced. The student doesn’t learn the terms voiced and unvoiced, but these terms do help us as adults discuss the various sounds.

The following exercise will help you distinguish between the two sounds of th. Say the two words aloud very slowly and listen for the difference in the sound that th makes:

mouth
smooth

In the word mouth, the th is unvoiced.
In the word smooth, the th is voiced (more “buzzing” is heard and felt).

Here are some more examples:

Unvoiced /th/, as in three:

throw
thorn
north
birthday
thirty

Voiced /th/, as in then:

bathe (The Egyptians bathed in the Nile.)
the
there
they
southern

Practicing these words slowly will help you recognize the “buzzing” that occurs in the voiced th so that you’ll easily be able to differentiate between the two sounds of th.

Photo by Paul Keleher