How big are the sound files?

Sound Effect files are very small. We have compressed it to 32 bit rate. 

Total Sound file size is 5mb. Including Background & Sound Effect

Does this still happen when you only load half the assets?

When i load Half Assets Loading Time will reduce a bit.

But i want to load all Sounds initially so that game wont be lags 

Try loading some at the start, then somewhere the user might actually stay for a while like a menu or another shorter loading screen between screens.

Yes.

But if i load inside the game then game freeze for a moment at that time. 

Any alternative solution?

Shorter but more frequent loading screens.

Is there any alternative solution? Since i dont want to preload  inside the game 

No unfortunately 

Okay. 

Just i want to know from user persepective. Which one is better?

1. Loading all at the beggining. Initial Loading Time is little more
2. Loading Some sounds at the transition from Menu to game