Theory

English words can be confusing because many have consonant pairs which have unexpected sounds.
For example:
PH sometimes has the sound of F as in PHOTO.
Other such words are TROPHY, ALPHABET, EMPHASISE, SPHERE, GRAPH, GEOGRAPHY.

Sometimes the combination PH sound like P-H.
For example:
PH in UPHEAVAL does not sound like F but like P-H.
Other such words are LOOPHOLE, UPHOLD, TOPHEAVY.

The combination SH can be confusing.
In some languages an H at the end of the word is silent, so words like ENGLISH are pronounced like ENGLIS.
In English, in the combination SH, the H is never silent.
The combination SH sounds like the SH in SHEEP.
Other such words are SHOW, ASH, CASH, SHAPE, SHIELD.

Another such combination is CH.
This can have two different sounds.
CH can sound like K, as in CHEMICAL.
Other such words are CHRISTIAN, CHORD, CHEMIST.

CH can also have the sound as in CHURCH.
Other such words are CHEAP, CHOKE, CHAT, CHIMNEY, ARCH.

The combination GH can also have different sounds.
In words like ROUGH, GH sound like F as in FIRE.
Other such words are ENOUGH, TOUGH, COUGH, LAUGH.

GH can also be silent as in the word THOUGH.
Other such words are THROUGH, THOUGHT.

The combination TH can also have different sounds.
TH can sound like THIS.
The sound of TH in the word THING is slightly different.
Other such words are BOTH, FROTH, CLOTH, PATH.

The combination WH sounds like a mixture of W and H, as in the word WHERE.
Other such words are WHAT, WHY, WHEN, WHICH, WHEEL, WHOLE.

Sometimes the combination can have a different sound as in the word WHO.

Another sound for this combination is the sound of H as in the word WHOLE, where the W is silent.

Finally, in the word ARROWHEAD, The sound of the W and the sound of the H sound as they would individually.