That's because the previous vowel gets dropped when the next word starts with a vowel sound. So what is said is technically "enferm-hoy" and you have to infer the gender or conjugation from context. In this case the speaker sounds very feminine so it is reasonable to assume and write "enferma hoy."
This exercise is very poorly constructed and trips people up for no good reason. I can't think of any legit pedagogical reason for deliberately providing a misleading context for an expected answer whose correct interpretation depends entirely on context! At the very least, either a masculine or feminine answer should be accepted. Either way, something has got to change.
At full speed IME there is a lot of vowel dropping and the audible difference between "enferma hoy" and "enfermo hoy" become negligible to my ears. I think part of the confusion is I'm talking about practical circumstances not any official grammar rules. I would love to hear from some native speakers about these real-world circumstances (not grammar rules), as my ears are relatively untrained in this language
Long story short, "lo/la/le" is used to refer to an object (thing or person, always a noun) that somebody/something is doing something to:
●Lo siento (I'm sorry/I feel it) = Yo siento/lamento eso/lo ocurrido (I feel/regret it/that/what happened).
●La veo (I see her/I see "feminine noun") = Yo veo a esa persona/cosa (I see that female person/feminine noun).
●Le escucho = Yo escucho a esa cosa/persona/Yo le escucho a usted (I hear something or somebody whose gender is unknown/I hear "formal you").
As you may see, the meanings depend on the context and intention of the speaker, but the format "lo/la/le + verb" is the same.
Not in this context. Given that the main part of the sentence is "yo estoy enfermo hoy (I'm sick today)", the meaning of "lo siento" (in this context) is "I'm sorry" most likely. But sure, you will find that "lo siento, [insert another sentence here]" may mean "excuse me" in other context.
Because estar (estoy) is used for feelings and temporary states.
So, because the subject is unwell, it's a temporary feeling and thus estar is used.
Working out when to use ser and when to use estar can be tricky. I generally just use temporary v permanent state as a quick way of doing it.
"ser"(to be) is used to define a permanent state(e.g. La falda es verde = The skirt is green; the skirt's color isn't a temporary state); "estar"(to be) is used to define a temporary state(e.g. Las llaves son en el escritorio = The keys are on the desk; the keys aren't always on the desk, it's just their current location(state).) If I got it right, I believe you can use ser in case you are talking about a permanent/chronical illness(I guess it would go something like "El es siempre enfermo"= He is always sick).
If you have the 'write what you hear' question, then you can't miss out the pronoun, because you have to write exactly what the voice is saying. However, if it was a question asking you to translate I'm sorry, I'm sick today into spanish then you could use estoy enfermo hoy without the yo.
While I feel adjectives should relate to the speaker's gender, here's a random thought. When listening to the voice at normal speed, something sounded odd - the end of the sentence sounded like "enfermoy". So I listened at slow speed (I didn't want to be marked wrong) and all was revealed - it was "enfermo hoy". Is it usual to run words together in such cases?
Eli, you use "yo estoy" when talking about how you are and where you are. (I.e. to talk about a condition you're in and about your location.) "Yo soy" is used when you're talking about who or what you are, and what you are like (i.e. your identity and any characteristics you have).
It does sound like the female speaker is saying enferma. I feel confused because the speaker is female and it is a masculine sentence. This should be considered in the future, esp. In a language that is so heavily influenced by gender. Also, wouldnt "yo estoy" be redundant? Why isnt it just "Lo siento, estoy enfermo"?