Hablar con fluidez
Fluency is not speed. It is having something to say while you work out what you actually mean, and knowing how to get back to the point afterwards. None of these carry much meaning; all of them are said constantly, and a B2 speaker who has none of them sounds like they are reciting.
Ganar dos segundos
a ver…
let me see…
A ver, ¿por dónde empiezo? · Let me see, where do I start?
The single most useful one. It buys a full second and sounds native.
es que…
the thing is…
Es que no me lo esperaba. · The thing is, I wasn't expecting it.
Introduces a reason or an excuse. Enormously frequent and almost never taught.
o sea
in other words
Llegó tarde, o sea, como siempre. · He turned up late — as usual, basically.
O sea reformulates in speech; es decir does the same in writing.
digamos
shall we say
Fue, digamos, una sorpresa. · It was, let's say, a surprise.
por así decirlo
in a manner of speaking
Same job as digamos, one register up.
no sé
I'm not sure how to put this
Often not literal. It softens what comes next: no sé, a mí me parece raro.
bueno…
right, so…
Opens almost anything, and buys time doing it.
pues nada
anyway, moving on
Very peninsular.
cómo te diría
how shall I put it
Buys the most time of any of these, and sounds thoughtful rather than stuck.
Volver al hilo
a lo que iba
back to my point
A lo que iba: necesitamos decidirlo hoy. · Anyway, as I was saying: we need to decide today.
volviendo a lo de antes
going back to what we were saying
por cierto
by the way
Opens a digression. A lo que iba closes it again.
a todo esto
which reminds me
A todo esto, ¿tú cómo lo sabes? · Anyway, how do you even know that?
Introduces something you have just remembered, often a question.
hablando de eso
speaking of which
dicho esto
having said that
Concedes the previous point and then turns.
en resumen
to sum up
Total que is the spoken version and much more common in conversation.
Matizar lo que dices
hasta cierto punto
up to a point
Tienes razón hasta cierto punto. · You're right up to a point.
en el fondo
deep down, really
En el fondo le da igual. · Deep down he doesn't care.
por lo visto
by all accounts
Por lo visto is spoken, al parecer slightly more neutral.
si te soy sincero
if I'm being straight with you
La verdad es que is more frequent and less dramatic.
no es que…, es que…
it's not that…, it's that…
No es que no quiera, es que no puedo. · It's not that I don't want to, it's that I can't.
A structure worth learning whole. It corrects a wrong assumption without contradicting anyone.
tampoco es que
it's not as if
Tampoco es que fuera tan caro. · It's not as if it was that expensive.
más bien
rather
No estoy enfadado, más bien decepcionado. · I'm not angry, more disappointed.
por lo menos
at least
Also al menos. Both fine.
Cerrar
en fin
oh well
En fin, ya veremos. · Anyway, we'll see.
y ya está
and that settles it
Closes a list or an argument.
y punto
and no more discussion
Firmer, and can sound abrupt: se hace así y punto.
qué remedio
what else can you do
Resigned acceptance. Very Spanish, and very frequent.
ya veremos
we'll find out in due course
Often a polite no.
el caso es que
the upshot is
El caso es que al final no fuimos. · Anyway, the point is we didn't end up going.