Alternate titles are important to add for any original titles that contain numbers or single letters to represent words, and/or slang.
These alternate titles help societies better identify your works, so if you have any ambiguous words it's best to clarify.
In Da Club (original title)
In The Club (alternate title)
On 2 the Next (original title)
On to the Next (alternate title)
You can also use an alternate title to include featured artists.
My Life (original title)
My Life ft. Eminem, Adam Levine (alternate title)
My Life ft. Eminem (alternate title)