Palatoalveolar

/ʃ/

It doesn't exist in Spanih. In some parts of Andalucia and Extremadura it is used instead of 'ch',
for example (...)

It may appear in: 

• Initial: ship, shut, shave
• Medial: fishes, fashion, dishes,
• final: wash, crash, rush

This is sound is usually written withe the letters 'sh'.

• shop, shop, finish

Other spellings:

• Russia, russian, sugar, Schothish, Irish, Swedish. Danish,

/ʒ/

There is no similar sound in Spanish. To produce it follow the same steps as for /s/ and use your voice

because (...). This sound is not found in inital position (except for some Franch words):

• Medial: lesure, treasure.
• Initial: garage

Spelling

Thes sound /ʒ/ is usually written with the letters 's' or 'ge': usua, pleasure, television.

• vision, explosion, decision, exclusion.