You cant when you delete them there lost forever. Unless your worlds backed up.
No, deleted worlds are unrecoverable.
No
There are no commands in minecraft PE as far as I know.
As of my last update, "The Crafting Dead" is a popular Minecraft mod that brings a zombie apocalypse experience to the game. However, it was primarily designed for the Java Edition of Minecraft and may not be officially available for Minecraft Pocket Edition (PE). There are similar zombie-themed mods and maps for Minecraft PE, but they may not replicate "The Crafting Dead" experience exactly. Always check the latest community forums or resources for any new developments related to mods for Minecraft PE.
there are no mods in minecraft pe i hope there will be
Yes. It is possible to crouch in the minecraft pe.
Depending on what you mean by "lose" your world it could be corrupted or not installed properly and you might have just acedently deleted it but if you did any of those thing I am sorry to tell you but think you will not be able to get it back.
If you have already purchased Minecraft PE, then update the game.
Minecraft PE 0.8.0 does not have squids in it.
There are no mods for Minecraft PE But it would be cool
there are no rumors for minecraft pe version 4.1
there is no jungle biome in minecraft PE