# Why do \large and \textbf require different usage of braces?

\large and other font size commands need to be placed inside a group:

In this text {\large some part} is large.


Whereas \textbf and other styling commands receive a parameter:

In this text \textbf{some part} is bold.


Why the difference?

• \large is a switch, whereas \textbf{...} is a command with an argument. The corresponding switch is \bfseries. Actually \textbf{...} is the same as {\bfseries ...} – Bernard Jun 7 '19 at 17:04
• Related, although the present question is phrased more clearly: Braces inside or outside? – barbara beeton Jun 7 '19 at 18:14

\textbf{stuff} (roughly) does {\bfseries stuff}, which is the counterpart for \large you are looking for. \textbf is defined in terms of \bfseries with:

\DeclareTextFontCommand{\textbf}{\bfseries}


You can do the same to create a \textlarge:

\documentclass{article}
\DeclareTextFontCommand{\textlarge}{\large}
\begin{document}
In this text \textlarge{some part} is large.
\end{document}