(0) Read the official Microsoft support guide, because otherwise you will never succeed.
https://support.microsoft.com/en-GB/office/change-sharepoint-online-language-settings-0f6a477a-dcab-4462-9d0c-e3b53d138183
Note that the UIs in the following steps may be in a language that you do not speak, but the support guide will naturally refer to the English localization. If you need the localized names of the UI elements, the guide is available in multiple languages. Unfortunately this will change the language of the entire guide, which may make it difficult to understand the steps themselves.
(1) Click on your profile circle in the top right and then click on this link.
(2) On the new page that opens, click this button.
(3) In the modal pop-up, click this unassuming one-word link in the bottom left.
(The link translates to "You can add more profile information here.")
(4) On the new page that opens, click on the ellipsis button to show the hidden items of the horizontal navigation.
(5) Select "Language and region".
(6) Add your preferred language using the drop-down box and move it to the top of the list using the little arrows.
(7) IMPORTANT! Don't forget to scroll to the bottom and click on "Save all and close"!
(8) Click "OK" on this pop-up.
(9) You're done and will be navigated back to the page from step 2!
Hope you didn't want to change any other settings here.
Oh, and the page from step 2 will still be in the original language. Don't worry, the pop-up dialog assured us it will change soon. Word may also still be in the original language, but should change sooner than the page from step 2 (I am still waiting on that one).
No it's not. You clearly have zero perspective on energy consumption.
The power draw on a phone with an NPU (where Gemini Nano is mostly used) is comparable to watching a video on your phone, maybe a couple of watts. On devices without NPUs (e.g. PCs) it will be more, but not dramatically so. The power use of this is absolutely zilch in the grand scheme of things.
To be extremely generous, let's say the average power draw is 50 watts, and that the model generates on average 10 tok/s, and that the average user has it generate 500 tokens per day (about 400 words). That's 50 seconds of 50 watts for every user, and let's say this is done by a billion users. This is a very generous estimate: in reality the average power draw is lower, the average tokens generated is likely lower (the intended use is generating short snippets like, say, email titles based on the email's content), and this definitely won't be used by a billion people.
WolframAlpha tells us that this takes 694 MWh of power, and helpfully mentions that this is 74% the fuel energy of an Airbus A330-300, and indeed this energy use is roughly in the ballpark of one transatlantic flight. There's about 500 transatlantic flights every day. Two offshore wind turbines will generate this much power on a windy day.
In all likelihood an order of magnitude more energy is spent every day watching short form videos. I'm not going to do the napkin math on that though.
edit: in reality, local models like this will likely reduce net power consumption as fewer API calls are made to cloud LLMs, which are both less power efficient and have overhead from the whole internet thing.