In which ways would life be different if the oceans were fresh water as opposed to being salt water? ~

Impossible to say. Life as it is today evolved in a saline environment. Even our blood has dissolved salts, necessary for our nervous system to work properly. I suppose life could have evolved in a fresh water environment and would possibly be similar to that of fresh water lakes. Other than that, I can't imagine anything else.

There would be no such terms as 'salty sailor' or 'an old salt'.

Ocean liners and large yachts wouldn't need desalination units aboard.

Southern California wouldn't be dependent on another U.S. state for their water.

Some species of sea animals would die. Tuna for one.

If the oceans remained freshwater, Earth would be a barren ball of ice or a lifeless "oven" like Venus.  The salinity in the oceans comes from rain/snow run-off.  For them to remain fresh water, would mean it never rained. 
As rain falls, it erodes the land (rocks, soil, minerals).  The minerals, acids and such in these materials along with sediment, are washed into rivers which in turn empty out into the oceans.  When the water in the oceans evaporates (to become rain once again) the other stuff is left behind, thus giving the seas their "salt" content.
The reason why the oceans haven't become a lifeless "salt mass"over the years is that sediments (dirt, sand) trap some of the "saltiness" below the seafloor.  Subduction (where the earth's crust is being pushed/pulled back down into the mantle) helps to "recycle" some of the seafloor.

Assuming evaporation still existed, the earth would have quickly become shrouded in a thick blanket of clouds.  Eventually, all the water on the planet's surface would be in the atmosphere.  This, coupled with normal CO2 (from volcanoes and such) would have either made the planet very hot (like Venus) or tuned it into a frozen ball of ice.  Either way, life as we know it could not have existed.

For starters, the oceans would be deeper and sea level the same everywhere. Right now the Atlantic is saltier than the Pacific, and the extra density pushes sea level about ten feet lower. That is why the Panama Canal has to have locks.

Here is an experiment you can do. Put a small amount of water in your nose. Notice that you don't like the feeling. Now mix 1/2 tsp salt in a cup of water and put that in your nose. That feels ok. The difference is why salt water fish usually don't swim into fresh water rivers and fresh water fish usually don't swim out. This post was edited by Not Sure at December 30, 2018 5:05 PM MST

it would probably be cleaner

Instead of hypothesizing,  let's desalanate all the oceans ...and find out.