Learn English – phrase/word meaning “visit a place for a short period of time”

English does not have a word referring to this range specifically. Different languages divide up the world differently - this is one of those cases where the languages don't have equivalent terms.

The word teen or teens is close, but it has two limitations:

1. "Teen" refers only to 13 - 19; it cannot refer to 11 or 12. Recently, the term "tween" has been coined to refer to the ages 10-12 for this very reason.
2. "Teen" is most often found in reference to abstract ranges such as ages, years, temperatures and the like. So while we might refer to a "temperature in the teens" to mean a temperature between 13 - 19 (C or F), it's less common to refer to use it with concrete objects. It would be unusual or even wrong to say "I have teens of apples".

Since there is no specific term, you should instead use constructions such as:

• Eleven to nineteen
• In the low two digits
• About 15, 15 or so, around 15, 15 give or take...
• More than ten but less than twenty
• Ten-something (I think this is more understandable and common than the alternative 'tensomething')
• There is a slang term that is close to the meaning and usage, but its use may be marked in certain contexts and it is informal: umpteen; "It'll cost umpteen thousand dollars."
• Or finally, reword your statement to avoid the situation

Your question seems to revolve around the probability that two things are different, not the degree to which they are different. Using basically refers to the degree they are different.

A quick look at dictionary definitions shows that probably is synonymous with most likely, however from usage, why would the phrase most probably then exist?

likely to be different

means a greater than a 50% chance

most likely to be different

means something much greater than 50%, for example 90%

are different
definitely different
inherently different
completely different
totally different

implies they are different with certainty (probability of 1.0)

To me, most likely has a greater chance of being different than just probably, whereas likely and probably are equivalent. However, in your example, most likely still leaves the door open that they may be different, which makes phrasing difficult since the degree can always be modified by more or very which would make it two words, not one word.