て form - Desconstructing らしくなってきたの

Let me disassemble this construction bit by bit to see if I get it right, ok?

So, の is the explanatory particle. The らしくな part comes from らしい. So らしくない is its negation. Now, I imagine that てきた is the motion 'suffix', right? So it would mean that something is 'coming to seem like' something else. This is actually how google translates it. My question is, why is らしい in the negative? Wouldn't it mean that something 'is not coming to seem like' something else? Plus... the てきた 'suffix' (I'm calling it a suffix for lack of knowledge of a better word, sorry) comes from the て-form + くる. らしい, however, is not a verb, so where does the て-form come from?

Thank you very much.

Answer

[...] why is らしい in the negative?

In fact, it is not the negative form. Brush up on い-adjectives conjugations.

You see, you're almost right on everything but that's らしい + なる, in the construction expressing something "becoming something/some way".

In this case that is done by adding く + なる because らしい conjugates as an い-adjective.

So, らしくなる.

What happens next is simply the て-form plus きた.

Hence らしくなってきた.

As you see, there is no negative.　To wrap it up:

らしい　→　らしくなる　→　らしくなって　→　らしくなってきた

To be negative you would have to add an extra なく:

らしくない　→　らしくなくなる　→　らしくなくなって　→　らしくなくなってきた

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To explain a little more, let's review a moment this form of expressing changes.

This is the basic construction rule:

い-adj （－い＋く）＋なる Example たかい　>>>　たかくなる

な-adj （－な＋に）＋なる Example きれいな　>>>　きれいになる

nouns （＋に）＋なる Example せんせい　>>>　せんせいになる

And when it comes to negative:

い-adj （－い＋く）＋ならない Example たかい　>>>　たかくならない

な-adj （－な＋に）＋ならない Example きれいな　>>>　きれいにならない

nouns （＋に）＋ならない Example せんせい　>>>　せんせいにならない

Which is basically the usual construction conjugating the verb なる into its negative form.