"I got this wallet from my mother."
I could be very wrong...i think having お in front of 母 adds politeness and would require an honorific after it. So, お母さん. You can't have one witbout the other. But i could be wrong. Very, very wrong.
Please be kind T_T
母 (はは）is the word 'my mother', when speaking to someone outside the family (or close friends) about her. Neither お nor さん should be affixed to this form. はは should be considered a 'clinical' usage of the word 'mother', therefore politeness modifiers would be awkward and unnecessary.
お母さん (おかあさん）is more flexible. It can be used for direct address TO 'one's own mother' as well as address OF the mother of a second or third party (your/his/her/their mother).
母さん (かあさん): The お can be dropped when addressing one's own mother or referencing her during dialog within a family (or familiar) unit. In some households, おかん (which is a contraction of お母さん) is even more familiar/casual.
Motherhood as a concept can use 母 (はは), お母さん, ママ, etc. 'She's going to be a mother' = 「(彼女は）母/お母さん/ママ になる。」
So, while お母さん can be used somewhat flexibly, 母 (はは) cannot. One can infer from the usage of 母 (はは) that the speaker is talking to someone outside of the family & friend zone.
Both はは and かあ are 訓読み (Kun'yomi - Japanese native readings). There are other, less used, readings which need not be addressed now. The main 音読み (On'yomi - Chinese-derived reading) is ぼ.
お母 does exist as a word, but it would be pronounced おかか, which is 'baby talk' for 'mommy'.
So, the short answer is: 母 (はは) by itself and words which use 母 as an element should be considered as different words because their usage is different (despite referencing the same subject/concept).
I feel like I might be answering my own question here, but as others have asked, it looks as though there's an inconsistency with how Duolingo handles this sentence structure. Another question in this section asks to translate "I get shoes from my dad," which would become 父につくをもらいます.
This sentence structure above is wrong when put in this setting. Duolingo doesn't accept 母にこのさいふをもらいました. What exactly is the difference here? I have an inkling (hence the answering my own question part), that this question has the topic highlighted (wallet), which is why a topic marker is used (は). The shoes example is more of a general statement, which is why there is no topic marker.
I guess what my real question is if the distinction really matters, as they technically mean the same thing.
I think you've figured it out yourself (where the focus lies). Your suggested translation should be accepted. If it was not, I would recommend reporting it.
On an unrelated note, 'shoes' would be くつ, not つく.
Why isn't this read as, "My mother got this wallet?"
I keep wanting to read this as: [as for this wallet] [my mother] [received (it)].
Thanks! から instead of に would have made it much easier to comprehend without previous understanding of the phrase, though I don't think it will be too hard to remember now that I understand.
I lived in Japan for 6 years and no one in my area used "ni" in place of "kara". Yes, it's technically correct, just from my experience it's sort of old sounding.
I also have anecdotal evidence of the other form being used often (usually in more formal settings). Both are valid, still taught, and still used (and not only by old-fashioned people).
While many Japanese are unaware of the difference in nuance, に emphasizes the 'receipt' of a thing while から emphasizes who it was received from.
See this link (only in Japanese) for a QA about this topic.
More information on くれる、あげる、もらう at Tae Kim's page.
Checking contemporary usage statistics, から is used slightly more than に, but not by much.
IDK. Maybe they're being sticklers and want you to use the は particle?
For now, I would just chalk it up to Duo being Duo.