Tired vs Sleepy

Living and teaching in Moscow, Russia for the last 14 years, I often notice interesting differences between the languages. My children, ages 10 and 4, who speak both languages, sometimes make interesting mistakes that illustrate these differences.

One mistake they make is in the usage of the Russian word for tired 'устать' (which
is a verb in Russian) and the word sleepy 'сонный'.

In English, the adjective 'tired' usually means the same as exhausted (often
from some sort of physical activity) like in the following examples:
examples.

I've worked all day and now at the end of the day I'm really tired.

I felt really tired after I ran around the block.

However, it can often mean the same as the adjective 'sleepy':

I'm tired so I'm going to bed.

I still feel tired even after 8 hours of sleep.

It is this latter meaning that is often surprising for Russian speakers. This is because in Russian, one uses the word for tired only in the meaning of being exhausted, such as after tiring physical activity or a long and difficult day. It is not simply a possible synonym for 'sleepy' as is possible in English. Therefore, it sounds really funny to hear it used by somebody who has just woke up. My youngest daughter often suprises my Russian nanny by saying "Не хочу вставть. Я устала." (I don't want to get up. I'm tired.) which often provokes the responce "От чего же ты устала?!" (What are you tired from?!)

Of course, in English, there is a distinction as in Russian, between the two words; however, some cases, especially in colloquial English, this distinction is not always so clear.