Not the parent commenter, but -- days of week in Polish are a nice example, IMO.
`Środa` means `Wednesday`, but depending on the grammatical case it's going to be translated either to `środa` or `środę` (or five more, but somewhat less likely to appear in UI [1]).
- Next <Wednesday> is 2018-01-03. = Najbliższa <środa> przypada na 2018-01-03.
- This event happens on <Wednesday>. = To zdarzenie ma miejsce w <środę>.
If you mix the variants, it's going to sound very off (but it will be understandable, so there's that).
What's more, days of week have different genders, which affects qualifiers:
- <this> Wednesday = <ta> środa (Wednesday is a "she")
- <this> Monday = <ten> poniedziałek (Monday is a "he")
... together with the grammatical cases affecting the qualifiers:
- <This> Wednesday is crazy. = <Ta> środa jest szalona.
- <This> Thursday is crazy. = <Ten> czwartek jest szalony.
I once worked with translating an application to polish, and found out we had to have separate placeholders for "name" for persons (nazwisko) and for things (nazwa).
Which is a simple example why you need context.
All UI frameworks should have a "translate" mode, where all labels and static text can be right-clicked and modified...
`Środa` means `Wednesday`, but depending on the grammatical case it's going to be translated either to `środa` or `środę` (or five more, but somewhat less likely to appear in UI [1]).
- Next <Wednesday> is 2018-01-03. = Najbliższa <środa> przypada na 2018-01-03.
- This event happens on <Wednesday>. = To zdarzenie ma miejsce w <środę>.
If you mix the variants, it's going to sound very off (but it will be understandable, so there's that).
What's more, days of week have different genders, which affects qualifiers:
- <this> Wednesday = <ta> środa (Wednesday is a "she")
- <this> Monday = <ten> poniedziałek (Monday is a "he")
... together with the grammatical cases affecting the qualifiers:
- <This> Wednesday is crazy. = <Ta> środa jest szalona.
- <This> Thursday is crazy. = <Ten> czwartek jest szalony.
- I'm busy <this> Wednesday. = Jestem zajęty w <tę> środę.
- I'm busy <this> Thursday. = Jestem zajęty w <ten> czwartek.
[1] https://en.wiktionary.org/wiki/%C5%9Broda