These are special suffixes only for the definite conjugation:

-lak, -lek

They are used with transitive verbs when the 1st PS form refers to the 2nd PS or 2nd PP! Think of them as:

I + transitive verb + you (sing. OR plur.)

Examples:

Szeretlek. – I love you.
Utállak. – I hate you.
Látlak. – I see you.
Nézlek. – I watch you.
Kérlek. – I ask you.

and so on…

As -lak, -lek can refer to both 2nd PS and 2nd PP, you can use the accusative pronouns if you want.

Szeretlek téged. – I love you.
Szeretlek titeket. – I love you (guys).

Of course, you can emphase the accusative pronouns:

Téged szeretlek.

Generally speaking, it is not necessary to add these accusative pronouns unless the context is ambiguous.

More next time.