1) for any continuous form we need two components: duration + moment.
The Present Continuous is used to indicate that the action is taking place right now:
To use the Present Continuous, you don't need to have words like now, today, etc in the sentence. They could be merely implied.
· I'm speaking English now. (right now)
· I'm speaking English. – (probably now or today)
· She is reading Shakespeare. – (now, today, this month, etc)
2) ... or precisely today, or this very week, this very month, etc:
· She is reading Shakespeare this week. – Она читает Шекспира на этой неделе. (именно на этой неделе)
· I'm speaking English now. – Я сейчас говорю по-английски. (прямо сейчас)
· She is reading Shakespeare this week. (this very week)