People often overestimate the clarity of their intentions in their electronic communications because they underestimate the importance of in communication.

People often overestimate the clarity of their intentions in their electronic communications because they underestimate the importance of tones of voice in communication.

Explanation:

Many factors intervene in communication together. We use words, we use non-verbal language through our gestures and attitudes, and we also use a certain tone of voice. If we focus on this last aspect, the tonality in the voice is decisive in many ways, which cannot be appreciated through electronic communications. With this we communicate emotions, attitudes and a degree of personal involvement. At the same time, the image we project on others largely depends on the tone of voice we have.

The first sentence who spoke that line was Cukita's father when his father was angry and used broken English that is why the sentence is like that.
The second sentence who spoke that line was Cukita's mother when someone stole her mother's idea about the heavy bags with wheels.
And the last one is Cukita spoke that line when she stood up for her siblings that time.