No, I haven't. No, I haven't.

No, I haven't. No, I haven't.

I've seen Beethoven's ninth on TV before, but I don't think I can sing or play that music sincbecause it's too difficult for me. I've seen Beethoven's ninth on TV before, but I don't think I can sing or play that music because it's too difficult for me.

You could use "since", but "because" is a bit more natural.

I've seen Beethoven's ninth on TV before, but I don't think I can sing or play that music sincethink it's too difficult for me to sing. I've seen Beethoven's ninth on TV before, but I think it's too difficult for me to sing.

Nothing technically wrong with what you've written, although "since" is generally used with a more specific reason. I have changed the ordering to cut down on repetition: "too ... for" is in itself a negative form, giving a nice way to compact the clause.

I've seen Beethoven's ninth on TV before, but I don't think I can sing or play that music sincit because it's too difficult for me. I've seen Beethoven's ninth on TV before, but I don't think I can sing or play it because it's too difficult for me.

In the first place, is thatit in English? In the first place, is it in English?

In the first place, is thatt's not in English?: In the first place, it's not in English:

The only time that you can pose a question in written English is the so-called "rhetorical question", where the answer is already obvious to the reader. This is used to mock anyone with a different viewpoint to the writer.

In the first place, is that English? In the first place, is that English?

It's apparently German. Some other classical songs are also in Latin

In the first placeFirst of all, is that even English? First of all, is that even English?

In the first place, is thatit in English? In the first place, is it in English?

I guess Beethoven is German, so I need to study the German language so that I canin order to sing that song. I guess Beethoven is German, so I need to study the German language in order to sing that song.

I guess Beethoven is German, so I need to study German language so that I can sing that song.would need to study German before I could attempt it! I would need to study German before I could attempt it!

"I guess" is a bit informal here. To avoid saying "German" twice, I think you can remove the reference to Beethoven without any loss of meaning. "That song" is not needed; it's clear what you're talking about, so "it" will do. Also, be wary of a common mistake - in a "song", singing is the key feature throughout; any other work of classical music is a "piece". As Beethoven's ninth is a symphony, we never refer to it (even the final choral section) as a song. Finally, for variety, I have replaced "sing" with "attempt", as the action is clear from the context.

I guess Beethoven is German, so I need to study the German language so that I can sing that song. I guess Beethoven is German, so I need to study the German language so that I can sing that song.

I guess Beethoven is German, so I would need to study German language so that I canto sing that song. I guess Beethoven is German, so I would need to study German to sing that song.

I guess Beethoven is German, so I need to study German language so that I can sing thate song. I guess Beethoven is German, so I need to study German so that I can sing the song.