For instance, we soon begin to notice that ‘T’ in German is often represented by ‘D’ in English, as _tag_ becomes _day_; _tochter_, _daughter_; _breit_, _broad_; _traum_, _dream_; _reiten_, _ride_; but sometimes by ‘TH’ in English, as _vater_ becomes _father_; _mutter_, _mother_. Again, ‘D’ in German is often equal to ‘TH’ in English, as _dorf_, _thorpe_; _feder_, _feather_; _dreschen_, _thrash_ (_thresh_); _drängen_, _throng_; _der_ (_die_), _the_; _das_, _that_. Now there is a certain likeness common to these three sounds, ‘T,’ ‘D,’ and ‘TH,’ as any one’s ear will tell him if he say _te_, _de_, _the_. As a matter of fact they are all pronounced with the tongue pressed against the teeth, only in rather different places; and in the case of the last sound, _the_,[27] with a breath or aspirate sent between the teeth at the same time. So we see that, these letters being really so much alike in sound, there is nothing at all extraordinary in one sound becoming exchanged for another in the two languages. We learn, therefore, to look beyond the mere appearance of the word, to weigh, so to speak, the sounds against each other, and to detect likenesses which might perhaps otherwise have escaped us. For instance, if we see that CH in German is often represented by GH in English--in such words as _tochter_, _daughter_; _knecht_, _knight_; _möchte_, _might_; _lachen_, _laugh_,--we have no difficulty in now seeing how exactly _durch_ corresponds to our _through_. For we have at the beginning the _d_ which naturally corresponds to our _t_, the _r_ remains unchanged, and the _ch_ naturally corresponds to our _gh_; only the vowel is different in position, and that is of comparatively small account. Nevertheless at first sight we should by no means have been inclined to allow the near relationship of _durch_ and _through_. Thus our power of comparison continually increases, albeit a knowledge of several languages is necessary before we can establish satisfactory rules or proceed with at all sure steps.