Purpose of adj+kucha (くちゃ) and noun+ja (じゃ) in this sentence


Though I think I've understood the gist of the following sentence, I struggle
to interpret two of the used terms.

> こんなに小さくちゃ一人じゃ生きていけないわよね。  
>  This small (cat) mustn't live alone. (?)

  1. What exactly does chisakucha mean? I read something online about verb+kucha ... ikenai being a structure to express must not in casual speech, but it was very vague (and this is an adjective).

  2. Is the ja in 一人じゃ a variation for だ ? Or does it mean so/then (as in cause so/then effect)?




> 「こんなに小{ちい}さく **ちゃ** 一人{ひとり} **じゃ** 生{い}きていけないわよね。」

「ちゃ」 is the informal/colloquial form of 「 **て** は」 and

「じゃ」 is the informal/colloquial form of 「 **で** は」.

Both are used frequently.

> 「I-adjective in 連用形{れんようけい} ("continuative form") + ては/ちゃ」

means:

> "if (i-adjective)"

And

> 「Noun or Stem of na-adjective + では/じゃ」

means:

> "if (noun/na-adjective)"

「小さく」 is the 連用形 of 「小さい」, so 「小さくちゃ」 means "if small" and

「一人じゃ」 naturally means "if alone" or "if all by oneself".

Thus, the sentence in question means:

> "If (you are/he is/it is) small like this, (you/he/it) could not live alone,
> could (you/he/it)?"

You ask:

> 2.Is the ja in 一人じゃ a variation for だ ? Or does it mean so/then (as in cause
> so/then effect)?

「で」 in 「では」 indeed comes form 「だ」.

「じゃ」 used in the sentence in question is **not** the conjunction 「じゃ/では」 that
you are asking about.




> 「こんなに小{ちい}さく **ちゃ** 一人{ひとり} **じゃ** 生{い}きていけないわよね。」

「ちゃ」 is the informal/colloquial form of 「 **て** は」 and

「じゃ」 is the informal/colloquial form of 「 **で** は」.

Both are used frequently.

> 「I-adjective in 連用形{れんようけい} ("continuative form") + ては/ちゃ」

means:

> "if (i-adjective)"

And

> 「Noun or Stem of na-adjective + では/じゃ」

means:

> "if (noun/na-adjective)"

「小さく」 is the 連用形 of 「小さい」, so 「小さくちゃ」 means "if small" and

「一人じゃ」 naturally means "if alone" or "if all by oneself".

Thus, the sentence in question means:

> "If (you are/he is/it is) small like this, (you/he/it) could not live alone,
> could (you/he/it)?"

You ask:

> 2.Is the ja in 一人じゃ a variation for だ ? Or does it mean so/then (as in cause
> so/then effect)?

「で」 in 「では」 indeed comes form 「だ」.

「じゃ」 used in the sentence in question is **not** the conjunction 「じゃ/では」 that
you are asking about.

