This (speaking) calculator comes equipped with an Audio Readout function.
It comes with a feature that reads out the names of the buttons pressed and the results of your calculations.

The audio readout gives the calculator a variety of potential applications:
it can be used as a child's toy, to spark an interest in numbers;
it can be used as a talking calculator for the elderly and others requiring visual assistance;
it can cut down on confusion in situations where counting is difficult, such as with long digits.

Features
・Readout can be switched to read both answers and buttons pressed, answers only, or buttons only.
・Adjustable voice pitch for audio readout
・Adjustable audio readout speed

*The great majority of device models can automatically download the text readout function
(if the audio function is not installed.)
However, some device models do not provide complete support for this, so please check the following settings:
Go to
Settings → Language and Input → Text-to-Speech output
and select your own language in the
Google Text-to-Speech Engine.
(If you have a different text-to-speech engine than the one above installed, the calculator's audio might not play.)