Learn Turkish: Kavşaktan sonra hızlanalım. - Let's accelerate after the intersection.

When using sonra (after) or önce (before) with a noun, Turkish requires that noun to take the ablative case (-dan/-den/-tan/-ten). You can think of it literally as saying 'after from the intersection'.

Why is the ablative suffix -tan instead of -dan in kavşaktan?

The word kavşak (intersection) ends in k, which is a voiceless consonant. Because of consonant assimilation (often remembered by the 'Fıstıkçı Şahap' rule), the d in the standard -dan suffix hardens into a t, making it -tan.

I recognize the word hız (speed). How does it become the verb hızlanalım?

The suffix -lan (or -len) is frequently used to turn nouns and adjectives into verbs. Adding it to hız (speed) creates the verb hızlanmak, meaning 'to gain speed' or 'to accelerate'.

What makes hızlanalım mean 'let's accelerate' rather than 'we are accelerating'?

The ending -alım is the first-person plural optative suffix, which translates to 'let us [do something]'. If you wanted to state a fact like 'we are accelerating', you would use the present continuous tense instead: hızlanıyoruz.