als vs. wenn

A genuinely new distinction, not a mapping from Malayalam

Malayalam's -മ്പോൾ ('when/at the time of') works identically whether you're describing a single past moment or a repeated, habitual, or future situation — no separate word is needed. German forces a choice: als exclusively for a single, completed event in the past, and wenn for everything else (repeated past events, present, future, or hypothetical). This isn't a comparison so much as a warning, like English's articles: build a fresh habit of asking 'was this a one-time past event?' before picking als or wenn, since Malayalam gives you no instinct to fall back on.