Yes, the letters E+A+R can also say other sounds. However, in those cases it isn't the phonogram EAR. You don't need to learn a new phonogram to read words like ear and bear, because these words can be decoded with the much more common phonograms EA + R. Students don't need to memorize a separate phonogram EAR in order to read them.
EAR saying /er/ is taught as its own phonogram because words like learn and search are not decodable without it.
This is a great question, because it gets at the heart of what a phonogram is.
First, for those new to LOE, here are three of the phonograms we teach:
- The phonogram EA says three sounds: /ē/ as in eat, /ĕ/ as in bread, and /ā/ as in steak.
- The phonogram R says /r/ as in run and errand. This is also a very common phonogram.
- The phonogram EAR says /er/ as in search.
Now, for the question.
In words like "learn" and "earn" and "search," the letters EAR are working together to say /er/. This is a unique sound made by these letters working together; the vowel sound is not one of the three sounds of the phonogram EA.
In the words "bear," "wear," "clear," and "near," EA says one of its usual sounds, /ā/ or /ē/, and R says /r/. The word "ear" contains two phonograms: the phonogram EA says /ē/, and R says /r/. Students can read these words as soon as they have learned the phonograms R and EA. They don't need to learn an additional phonogram in order to decode these words correctly, because they already know the sounds of EA and R.
Knowing the usual sounds of EA and the sound of R, however, does not equip you to sound out "search." This means that something different is happening with EAR here; it is its own phonogram.
A multi-letter phonogram is a group of letters working together to say a unique sound that they wouldn't say otherwise. The same letters can sometimes function as separate phonograms, saying their individual sounds, when adjacent to each other. The fact that a phonogram exists and makes a unique sound doesn't mean that every instance of those letters is that phonogram. So when your students come to a word with the letters E+A+R, they may need to try multiple possibilities to see which one works.
While we are asked most often about EA+R, other letter combinations also appear sometimes as a multi-letter phonogram and sometimes as separate phonograms. Consider the e-r in "ferret," the t-h in "hothead," the e-a in "reality," and the s-i in "enthusiasm." In each of these words, the letters work as single-letter phonograms, each one saying its own sound, rather than as the multi-letter phonograms er, th, ea, or si.
Note: There is in fact one other unique sound of EAR, but it is so uncommon that we do not teach it as a basic sound of the phonogram. EAR says /ar/ only in the very old English words "heart," "hearth," "hearken," and their derivatives.
British English Note: Some people teaching Logic of English, particularly those speaking British English, have also asked about teaching EAR as a distinct R-controlled long vowel, as in "wear" or "hear." This is because the R alters the shape of the long /ē/ or long /ā/ sound in our mouths, in some dialects particularly. We find that the vowel sound is similar enough that students can read and spell words with EA+R correctly without learning the combination as a separate R-controlled phonogram, but it is fine to teach it that way if you prefer and it makes sense with your dialect.