Learn Swedish: Hon syr klänningen med nål och tråd. - She sews the dress with needle and thread.

Here, med is acting as an instrumental preposition. In Swedish, when you want to express what tool or material you use to perform an action, you use med (meaning "with" or "using"). You will see this rule apply to almost all tools, such as writing med en penna (with a pen) or eating med kniv och gaffel (with a knife and fork).

Why is there no article before nål och tråd?

In English, you might naturally say "with a needle and thread," but Swedish frequently drops the indefinite article (en or ett) after med when referring to tools or materials in a general, functional way. Nål och tråd functions as an established pair here, describing the method of sewing rather than focusing on one specific needle.

Why does the verb syr only end in an -r instead of -ar or -er?

The infinitive of the verb is att sy (to sew). It belongs to a group of short verbs in Swedish whose stems end in a long vowel. Instead of adding -ar or -er to form the present tense, you simply add an -r directly to the infinitive. Other common verbs that follow this exact pattern include att bo becoming bor (live) and att tro becoming tror (believe).